GB2256060A

GB2256060A - "exposure control apparatus of camera"

Info

Publication number: GB2256060A
Application number: GB9208332A
Authority: GB
Inventors: Osamu Sato; Satoshi Nakano; Isamu Hirai; Toshiyuki Kitazawa; Takayuki Sensui; Masato Yamamoto; Toshimasa Yamanaka; Takenao Shishikura; Akio Takahashi; Nobuhiko Matsudo
Original assignee: Asahi Kogaku Kogyo Co Ltd
Current assignee: Pentax Corp
Priority date: 1991-04-15
Filing date: 1992-04-15
Publication date: 1992-11-25
Anticipated expiration: 2012-04-15
Also published as: AU649804B2; FR2675277B1; HK36495A; CA2066064A1; GB2256060B; FR2675277A1; CA2066064C; DE4212660C2; DE4212660A1; MY110099A; GB9208332D0; AU1489192A

Description

' n- " C-3 6 ' ' e)J EXPOSURE CONTROL APPARATUS OF CAMERA The present

invention relates to an exposure control apparatus of a camera having a plurality of exposure modes.

In a conventional camera having a plurality of exposure modes, a photographer can select a desired exposure mode by actuating an associated switch or button, etc.

In a recent camera having modes other than the exposure modes, such as a continuous shot mode, etc., the mode selection is effected by actuating a plurality of switches in combination.

However, ordinary photographers do not frequently use all of the exposure modes. Namely, only a few specific exposure modes are used. Therefore, for ordinary photographers, the need to actuate several switches in combination to select a mode is troublesome and complicated.

Furthermore, in a program exposure mode of a known camera, a shutter speed and a diaphragm value are automatically determined in a certain relationship (combination), and accordingly, it is impossible for the photographer to set optional shutter speed and diaphragm relationshiD values which do not satisfy the predetermined relationship while in the same mode. For example, when an operation switch is actuated in a program exposure mode of a known camera, both the shutter speed and the diaphragm value are modified simultaneously while maintaining a specific therebetween, and accordingly, it is impossible to vary only the shutter speed or diaphragm value. Consequently, if the photographer wants to vary only the shutter speed or diaphragm value while in the program exposure mode, it is necessary for the photographer to first switch the program exposure mode to a diaphragm priority automatic exposure mode or a shutter speed priority automatic exposure mode.

Furthermore, in a manual exposure mode of a known camera, the photographer manually sets the optimum shutter speed and diaphragm value, while observing an exposure meter provided in a field of view of a finder. Namely, since the photographer manually sets both the optimum shutter speed and diaphragm value by himself of herself, it is possible for him or her to create more artistic or technical pictures.

However, the adjustment of both the shutter speed and diaphragm value is troublesome, especially for the ordinary photographer. In particular, if one of either the shutter speed or diaphragm value is readjusted after the shutter - 3 speed and the diaphragm value are adjusted to obtain an optimum exposure value, the other of either the diaphragm value or shutter speed must also be readjusted to maintain the optimum exposure value, which changes as a result of the readjustment.

1 An object of the present invention is to eliminate the above-mentioned drawbacks of a known exposure control system having a plurality of exposure modes by providing a simple exposure control apparatus in which, if one of the exposure factors (diaphragm value and shutter speed) is varied in the manual exposure mode, the other exposure factor is automatically adjusted so as to obtain an optimum exposure value by a simple operation.

According to the present invention, there. is provided an exposure control apparatus of a camera having a manual setting means for manually and independently setting a pair of exposure factors, including a shutter speed and a diaphragm value.

The exposure control apparatus further includes an exposure value locking means for locking an exposure value determined in accordance with the exposure factors and an exposure factor varying means for varying one of the exposure factors, based on the locked exposure value, when - 4 the other exposure factor is varied by the associated manual setting means.

With the above provisions, it is possible for a photographer to vary only the shutter speed or diaphragm value without first switching the program exposure mode to, for example, a diaphragm priority automatic exposure mode or a shutter speed priority automatic exposure mode, and without breaking the predetermined relationship between the values.

- 5 An example of the present invention will be described below in detail with reference to the accompanying drawings, in which:

Figure 1 is a plan view of a single lens reflex camera to which the present invention is applied; Figures 2 and 3 are a back view and a front elevational view of a main part of a single lens reflex camera shown in Fig. 1, respectively; Figure 4 is a block diagram of a circuit arrangement of a single lens reflex camera shown in Fig. 1; Figure 5 is a flow chart of a main operation of a CPU, embodying the present invention; Figure 6 is a timing chart of a communication operation between a CPU and an IPU, according to the present invention; Figure 7 is a flow chart of an automatic exposure mode operation, embodying the present invention; Figure 8 is a flow chart of an error correcting operation, embodying the present invention; Figure 9 is a flow chart of a hyper-program exposure mode operation embodying the present invention; Figure 10 is a diagram of a hyper-program exposure mode shown in Fig. 9; Figure 11 is a flow chart of a limited program exposure mode operation, embodying the present invention; Figure 12 is a diagram of a limited program exposure mode shown in Fig. 11; Figure 13 is a flow chart of a hyper-shutter speed priority automatic exposure mode operation, embodying the present invention; Figure 14 is a flow chart of a hypershutter speed priority automatic exposure mode operation', of another embodiment of the present invention; Figure 15 is a diagram of a hyper-shutter speed priority automatic exposure mode shown in Figs. 13 and 14; Figure 16 is a flow chart of a hyper-diaphragm priority automatic exposure mode operation, embodying the present invention; Figure 17 is a flow chart of a hyper-diaphragm priority automatic exposure mode operation, of another embodiment of the present invention; Figure 18 is a diagram of a hyper-diaphragm priority automatic exposure mode shown in Figs. 16 and 17; Figure 19 is a flow chart of a LA manual exposure mode operation, of still another embodimentof the present invention; Figure 20 is a flow chart of an LM manual exposure mode operation, embodying the present invention; Figure 21 is a flow chart of an LM aperture priority automatic exposure mode operation, embodying the present :r Q 1 1 ipu, embodying Fiaure 27 invention; Figures 22 and 23 are flow charts of an LA bulb and LM bulb exposure mode operation, respectively, embodying the present invention; Figure 24 is a flow chart of- an LA hyper-manual exposure mode operation, embodying the present invention; Figure 25 is a view showing an example of a hyper-manual select flag; Figure 26 is a flow chart of a main operation of an the present invention; is a flow chart of a communication operation between an IPU and a taking lens, embodying the present invention; Figure 28 is a flow chart of a switch input operation; Figure 29 is a flow chart of a Tv electronic dial operation; Figure 30 is a flow chart of an Av electronic dial operation; Figure 31 is a f low chart of a shutter speed changing operation as effected by a Tv electronic dial; Figure 32 is a flow chart of a diaphragm value AV changing operation as effected by an Av electronic dial; Figure 33 is a flow chart of a mode shifting operation; Figures 34A and 34B are together a flow chart of a mode selecting operation; Figure 35 is a flow chart of a checking operation; Figure 36 is an example of data storage in a RAM of an IPU; Figure 37 is a flow chart of a memory locking operation; Figure 38 is an example of a memory lodking flag in a RAM of an IPU; Figures 39A, 39B, 39C, 39D, 39E, 39F, 39G and 39H are flow charts of an indication operation, embodying the present invention; Figure 40 is a flow chart of an Ev checking operation, embodying the present invention; Figures 41A, 41B, 41C, 41D, 41E, and 41F show an indication of an LCD panel and an indication unit within a finder shown in various initial indication positions; Figures 42A, 42B, 42C, 42D, 42E, 42F, 42G and 4211 show various exposure modes indicated on an LCD panel and an indication unit within a finder; Figures 43A, 43B and 43C show various exposure modes in a lens manual mode, as indicated on an LCD panel and an indication unit within a finder; Figures 44A and 44B are modified flow charts of an indicating operation of a hyper-program shown in Fig. 39A; Figure 45 is a flow chart of a sub-routine of a -a - 9 second Tv dial checking operation; and, Figure 46 is a flow chart of a sub-routine of a second Av dial checking operation.

Figure 47 is a plan view of a single lens reflex camera having an exposure control apparatus embodying the present invention; Figure 48 is a block diagram of a control circuit of the exposure control apparatus shown in Fig. 47; Figure 49 is a flow chart of L main operation of a CPU of a control circuit shown in Fig. 48; and, Figures 50 and 51 are flow charts of a manual exposure control of a control circuit shown in Fig. 48.

1 The invention will be discussed below with reference to the preferred embodiments of the present invention.

Figures 1 and 3 are a plan view and a front elevational view of a single lens reflex camera body having an exposure control apparatus embodying the present invention, respectively. Figure 2 is a back view of a DX code reading portion of the camera body shown in Figs. 1 and 3.

A camera body 11 has a grip portion 13 which is provided, on a front end (i.e., the object side) of an upper surface thereof, with a shutter button 15. A Tv electronic dial 17 and an Av electronic dial 19 are provided behind the shutter button 15 and on an upper end of the back surface of the grip portion 13, respectively. Both the Tv electronic dial 17 and the Av electronic dial 19 are in the form of rotary dials which will be discussed below in detail. When the Tv electronic dial 17 and the Av electronic dial 19 are rotated, the shutter speed Tv, the diaphragm value Av and the exposure mode can be changed. The Tv electronic dial 17 and the Av electronic dial 19 constitute part of first and second manual setting means or first and second shutter speed and diaphragm value manual setting means, respectively.

A clear button 23 is provided on the upper portion of 1 the back surface of the camera body 11 in the vicinity of the Av electronic dial 19. A hold button 25 is provided on the right side of the clear button 23. The clear button 23 constitutes a part of a clear switch means.

The electronic dials 17 and 19, the clear button 23, and the hold button 25 are arranged so that when a photographer holds the camera body 11 in a normal posture, they can be actuated by his or her thumb or forefinger without having to shift the camera body 11.

A slidable exposure correction/ISO lever 27 and a slidable exposure mode/drive lever 29, both being slidable in opposite directions from a neutral on the top surface of the camera body position are located 11 to the left of a pentagonal prism. A main switch 31 is located on the top surface of the camera body 11 to the right of the pentagonal prism and can be moved to three different positions in a slidable manner.

DX pins DX1 - DX6 are provided in a patrone receiving chamber 33 of the camera body 11 and come into contact with DX codes, which are printed on the surface of a patrone of film, to thereby read the data. In particular, the DX pins DX1 -DX6 are brought into contact with the portion of the DX codes which represents the ISO sensitivity Sv, so as to read the data thereof.

A group of mount pins (CONT, RES/Fmin3, SI/Fmin2, Fmaxl, A/M, Fmax2, and -SCK- /Fminl) are provided on a body mount 35 of the camera body 11 to effect, for example, data communication between the camera body 11 and a taking lens 65 (Figure 4). When the body mount 35 is attached to a lens mount of the taking lens, the mount pins of the body mount 35 are electrically connected to the corresponding mount pins of the taking lens, so that the camera body 11 can read lens data, including a minimum F number Fmin (open F number) and a maximum F number, from the taking lens and perform data communication with a control means (ROM or CPU). The control means (ROM or CPU) is provided in the taking lens to read additional lens data, such as focal length data f, or data representing the kind of taking lens attached, etc. Note that a mark or a symbol, and a suffix I]-to (e.g., -SCK as mentioned above) represent an active low or an inverted value in this specification.

Figure 4 shows a circuit arrangement of a control unit of a camera system embodying the present invention.

The camera body 11 has CPU 41 and IPU 43 as a control means. The CPU 41 performs the fundamental photographic calculations and control functions, such as the calculation and determination of the exposure factors (i.e., diaphragm value Av and shutter speed Tv), exposure control, data necessarv for automatic focus control, etc., with a prefix 11-11 calculation of - 13 etc. The CPU 41 also functions as a means for compulsively changing the mode, returning an exposure mode, changing a priority exposure factor, compulsively changing an exposure mode within a specific exposure mode, setting a limit value, holding an exposure value, manual shifting, and switching a set mode.

The IPU 43 functions as an input interface of the switches, such as the shutter button 15, the Tv electronic dial 17, the Av electronic dial 19, etc. The IPU 43 also functions as an exposure mode setting means, a means for controlling the indicators, a regulator for making the power source of the CPU 41 ON and OFF (power holding), and memory means for storing the set data and shutter speed Tv, etc. The IPU 43 has a ROM 43a which stores programs determining the input of the switch data, indication of modes, communication with the CPU 41, communication the taking lens, etc.

for the with The IPU 43 also has a RAM 43b which temporarily stores the set modes, the shutter speed Tv, and the diaphragm value, etc. The IPU 43 further has an E 2 PROM (EIPROM) 43c which holds the number of film, the ISO sensitivity, etc., even after the camera power source is turned OFF.

The IPU 43 communicates with the taking lens 65 and receives lens data, such as a maximum F number Fmax, the minimum F number Fmin and the focal length f, etc. The IPU 43 communicates with the CPU 41 to transmit and receive the data therebetween to control the photographic operation and the indication of the data.

The output of a light receiving element 45 is logarithmically compressed by an operational amplifier 47 and a diode Dl, amplified by an amplifier 49, converted to a digital value (Bv, BV) corresponding to an apex value by an A/D converter 51, and input to the CPU 41 through input ports P30 P37.

The A/D converter 51 operates at a predetermined time to input the level signals of the ports P30 - P37 to the CPU 41 which reads object brightness signals and diaphragm value signals set by the taking lens 65 and converts the signals to corresponding apex values. The port P40 is an input switching control- port which switches the logarithmically compressed voltages amplified by the amplifier 49 and the diaphragm voltages set by a diaphragm volume 53. The diaphragm volume 53 generates diaphragm voltage which corresponds to the value set by the photographer when rotating the diaphragm ring (not shown) of a taking lens in the manual mode.

Ports P10 - P14 of the CPU 41 are connected to the DX pins DX2 - DX6. The CPU 41 checks the levels of these ports P10 - P14 at a predetermined time to read the ISO sensitivity Sv. The CPU 41 then stores the input data c including the diaphragm value Av, the object brightness Bv and the ISO sensitivity Sv, etc., in a RAM 41b at predetermined addresses.

A winding motor 55 winds and rewinds the f ilm, and a mirror motor 57 moves a mirror up and down. The operations of the motors 55 and 57 are controlled by the CPU 41 through a motor drive circuit 59.

A release magnet RL releases the mechanical engagement of the shutter to begin the release operation. A shutter mechanism (shutter curtain) thus released from the mechanical engagement by the release magnet RL is disengageably engaged by a leading curtain trailing curtain magnet ES2, so that the shutter curtain is controlled thereby. A EE stops the stop-down operation of the magnet ES1 and a movement of the diaphragm magnet the taking lens diaphragm. The operations of these magnets are controlled by the CPU 41 through a magnet drive circuit 61.

An EE pulse counter 63 aenerates EE pulses in 1 association with the stop-down operation, which iE associated with the up- down movement of the subsequent to the shutter release and sends the in turn mirror, outputs thereof to the port PDD of the CPU 41. The CPU 41 counts the level change of the port PDD and when the counted number reaches a value corresponding to the set diaphragm value Av, the diaphragm magnet EE is turned ON through the - 16 magnet drive circuit 61 to stop the stop-down operation thereby maintaining the diaphragm value Av.

Ports PLO- PL6 of the CPU 43 are connected to the mount pins (A/M, CONT, RES/Fmin3, SI/Fmin2, Fmaxl, Fmax2, -SCK-/Fminl) thereby completing an electrical connection to the taking lens 65 (i.e., memory or control means thereof). The IPU 43 communicates with the taking lens 65 through the ports PLO - PL6 to read the lens data including the open F number Fmin, the maximum F number Fmax, the focal length f, etc.

The taking lens 65 has a lens auto/manual selection switch 67 which switches between a manual diaphragm mode (lens-manual (LM) mode) and. an automatic diaphragm mode (lens-auto (LA) mode) in association with a diaphragm ring.

The lens auto/manual selection switch 67 is connected to an input port PLO of the IPU 43 through the mount pin Affl. The IPU 43 determines the existence of the manual diaphragm mode or the automatic diaphragm mode in accordance with the level of the port PLO. The "lens-auto mode" mentioned above is an automatic diaphragm mode in which the stop-down mechanism of the camera continues the stop-down operation until the diaphragm value becomes a predetermined value which has been set in the camera body. The "lens manual mode" mentioned above is a manual diaphragm mode in which the diaphragm value is manually set on the taking lens side. The lens-auto mode will also be referred to as a "body set" hereinafter.

Input ports PCO - PC2 and PBO - PB5 of the IPU 43 are connected to a main switch SWMAIN, a photometer switch SWS, a release switch SWR, an exposure mode switch SWMODE, a drive switch SWDRIVE, an exposure correcting switch SW EF, an ISO sensitivity setting switch SWISO, a clear switch SWCL and a hold switch SWHOLD, respectively.

The main switch SWAIN is associated with the main switch lever 31. The photometer switch SWS and the release switch SWR are associated with the shutter button 15. The switch SWS remains open until the shutter button 15 is depressed by a half step at which point it is turned ON. The switch SWR is turned ON when the shutter button 15 is depressed by full step. The exposure mode switch SWMODE and the drive switch SWDRIVE are associated with the exposure mode/drive lever 29. The exposure correcting switch SW EF and the ISO sensitivity setting switch SWISO are associated with the exposure/ISO lever 27. The clear switch SWCL and the hold switch SWHOLD remain open until their respective associated buttons, clear button 23 and hold button 25, are effected.

The IPU 43 detects the ON/OFF state of the switches SW, mentioned above, in accordance with the input levels of the input ports PC and PB of the IPU 43 to perform the - 18 necessary operations.

A pair of input ports PAO and PAl and another pair of input ports PA2 and PA3 of the IPU 43 are connected to the TV electronic dial 17 and the Av electronic dial 19, respectively. Each of the TV electronic dial 17 and the Av electronic dial 19 has a click-stop rotation mechanism per se known. For example, a pair of input ports PAO and PAl are in a floating state at a click-stop position, when the electronic dials 17 and 19 are rotated in a clockwise or counterclockwise direction, the level of one of the input ports first drops to "L" and then the level of the other drops to level "L", in accordance with the direction of the rotation of the dials. Thereafter, the one input port, the level of which has dropped to level "L" prior to the other, is returned to the floating state prior to the other. Since the order of change in the level of the input ports PAO and PAI or PA2 and PA3 depends on - the rotation of the dials, the IPU 43 can discriminate the direction of rotation based on the order of change.

A group of ports PLCD and PD of the IPU 43 are.confiected to an LCD display panel 69 and an indicator 71. The indicator 71 is located in the finder. The LCD panel 69 is controlled by the IPU 43 to indicate various photographic information, such as the exposure mode, the shutter speed Tv, the diaphragm value Av, the number of remaining frames c - 19 in a roll of film, the drive mode and other data (i.e., ISO sensitivity data, and exposure correcting data EF, etc.). The indicator 71 within the finder has indicating elements 71a and 71b (Figure 42E) which indicate the shutter speed Tv, the diaphragm value Av, and an under- exposure, over-exposure or optimum exposure of the film. The indicator 71 also has an indicating element 71c which indicates whether or not the memory is locked.

The main circuit structure of the camera system embodying the present invention, as discussed above, operates as follows. Note that the values of the shutter speed Tv, the diaphragm value Av, and the object brightness Bv in the arithmetic operation discussed below are all those used in calculating the APEX values.

- 20 Main Operation of CPU The main operation of the CPU 41 will be discussed below with reference to the flow chart shown in Fig. 5. The main operation is carried out in accordance with the program stored in a ROM 41a of the CPU 41.

When the photometer switch SWS is turned ON after the main switch SWMAIN is turned ON, electrical power is supplied to the CPU 41 and the operation shown in the flow chart of Fig. 5 is performed.

The CPU 41 first initializes all the input ports P at step Sll, and then initializes the RAM 41b at step S12. Thereafter, the DX code (ISO sensitivity SV), the object brightness Bv, and the diaphragm value Av set by the diaphragm volume 53 when in the LM mode, are input to the CPU (steps S13, S14 and S15).

Thereafter, the CPU 41 communicates with the IPU 43 to receive the necessary data, such as the set photographic exposure mode and the exposure factors, etc., from the IPU 43 (step S16).

The control exposure factors proceeds to step S18 in which the calculation is effected to obtain optimum exposure in accordance with the selected photographic exposure mode, the calculation being based on the ISO sensitivity Sv and the object brightness Bv, etc.

Thereafter, the CPU 41 performs data communication with Lh IPU 43 to send the calculated exposure factors (i.e., shutter speed Tv and diaphragm value Av) to the IPU 43 (step S19).

After the exposure factors are determined, the control proceeds to step S20 where it is determined whether or not the release switch SWR is turned ON. If the release switch SWR is turned ON, the releasing operation is effected (step S21). If the release switch SWR is turned OFF, the control is returned to step S13. While the power is held (i.e., while the power continues to be supplied), the operations of step S13 to step S20 are repeated.

43.

Data Communication with IPU The CPU 41 performs data communication with the IPU The data communication will be explained below with reference to Fig. 6 and Table 1 (page 111).

Each of. the CPU 41 and IPU 43 has terminals corresponding to CE, READY, SCK-, and DATA which are connected to each other.

The CPU 41 raises the level of the terminal CE shown), so that IPU 43 is ready for communication. When IPU 43 monitors the level of the terminal CE which changed from "L" to "H", the level of the terminal READY is dropped and then raised, so that interruption by the CPU is permitted.

(not the is 41 When the CPU 41 monitors the permission to interrupt, a clock signal is output to the terminal -SCK-(not shown), and a command is output to the terminal DATA. Upon completion of receipt of the command, the IPU 43 drops and then raises the level of the terminal READY, so that the CPU 41 detects the completion of the receipt. The IPU 43 outputs data corresponding to the received command in accordance with the clock signal sent from the terminal -SCK- of the CPU 41, or receives data from the CPU 41.

When the communication of the necessary data is completed, the IPU 43 drops the level of the terminal READY. Thereafter, the CPU 41 drops terminal CE, so that the IPU 43 detects that the data communication with the CPU is completed. When the IPU 43 monitors the level drop of the terminal CE, the IPU 43 raises the level of the terminal READY to finish the data communication.

AE Sub-routine The subroutine for (automatic exposure mode) at below with reference to the flow In this AE process, the sensitivity are converted to Sv) at step S50. The DX the level of the calculating the exposure step S18 will be discussed chart shown in Fig. 7.

DX codes representing the ISO APEX values (film sensitivity codes of the ISO sensitivity consist of 5 bit signals and are read by the five DX pins (5 bits) DX4, DX3, DX2, DX5 and DX6 which come into contact with the codes in the illustrated embodiment. The upper three bits (DX4, DX3 and DX2) constitute an integer and the lower two bits (DX5 and DX6) a decimal. For example, if the decimal is 110111 or "111', the APEX value is 0/3, if the decimal is 111011, the APEX value is 1/3, and if the decimal is "OW, the APEX value is 2/3. The decimal thus converted to the APEX value is added to the integer. For example, the DX code of ISO 100 is represented by Sv=5, since the integer "1011' is converted to an APEX value "S" and the decimal "01" is converted to an APEX value 11011.

Thereafter calculating (step S51 the object brightness Bv is converted to a object brightness BVD suitable for calculation by using the following equation: BVD=Bv + 7, Thereafter, the film sensitivity Sv and the exposure correcting value Xv are converted to a calculating sensitivity SVD and a calculating exposure correcting value WD suitable for calculation by using the following equations, respectively (step S52):

SVD=Sv- 1; WD=4- Xv The above-mentioned operations are effected not only to prevent the values of the calculating exposure factors BVD, SVD, XVD from being negative, but also to unify the accuracy or precision of the exposure factors to be a 1/8Ev - 24 step. Consequently, the APEX calculation (i.e., addition and subtraction) can be easily effected without considering the calculation accuracy. Note that since the precision of Sv and Xv is within 1/3 Ev, it is in theory impossible to convert them to values of a 1/8Ev step. To this end, Sv and Xv are rounded to approximately 1/3Ev and 2/3Ev to 3/8Ev and 5/8Ev, respectively.

Thereafter, the brightness correction value MNI) depending on a change of the open F number, is calculated at step S53. The brightness correction value MND is adapted to correct the object brightness Bv so as to maintain the exposure on a film plane at a constant value, regardless of, for example, a change in the open F number (i.e., change in brightness of the lens) during zooming and is a value peculiar to the taking lens. The brightness correction value MND is input from the taking lens by communication of the IPU 43 with the taking lens (IPU-1ens communication), which will be discussed hereinafter, and is transferred from the IPU 43 to the CPU 41 through the CPU-IPU communication at step S16.

Thereafter, the calculating exposure value WD is calculated, based on the calculating object brightness BVD, the calculating sensitivity SVD, the calculating exposure correcting value XVD, and the brightness correcting value MND by using the following formula; -Z LVD=BVD + SVD + XVD + MND TheCPU 41 detects the selected exposure mode and calls the exposure factor calculating sub-routine corresponding to the selected exposure mode (steps S55-1- S55-n, S56-1- S56-n). The diaphragm value Av and the shutter speed Tv are then calculated in accordance with the algorithm of the selected exposure mode. Thereaf ter, the control is returned. If an incorrect exposure mode is set, an error operation as described below is carried out (step S57).

Error Operation In the error operation at step S57 (Figure 8), the calculating shutter speed TVD and the calculating diaphragm value AVD are replaced with a calculating maximum shutter speed TVDMAX and a calculating maximum diaphragm value AVDMAX, respectively, and the number PN (or Pno) of EE pulses is set at the maximum value, i.e., 225. Thereafter, the calculating shutter speed TVD (the calculating maximum shutter speed TVDMAX) and the calculating diaphragm value AVD (i.e., the calculating maximum diaphragm value AVDMAX) are converted to values suitable for transmission to the IPU in processes labeled TVDT (TVD-TVT) and AVDT (AVDAVT), as explained in detail hereinafter (see Fig. 8).

Thereafter, the control is returned.

It is possible to replace one or both of the calculating shutter speed WD and the calculating diaphragm value AVD with a calculating minimum shutter speed TVDMIN and a calculating minimum diaphragm value AVDMIN, in place of the calculating maximum shutter speed WDMAX and the calculating maximum diaphragm value AVDMAX, respectively.

Exposure Calculating Sub-routine In the illustrated embodiment, the exposure modes include a program automatic exposure mode in which the shutter speed and the diaphragm value are automatically set in accordance with the object brightness, a shutter speed priority (EE LA) automatic exposure mode (lens-auto mode) in which the diaphragm value is automatically set in accordance with the manually set shutter speed and object brightness, a diaphragm priority (ES LA) automatic exposure mode in which the shutter speed is automatically set in accordance with the manually set diaphragm value and object brightness, a manual exposure (Manual LA) and bulb exposure (Bulb LA) modes, and a diaphragm priority (ES LA) automatic exposure mode (lens-manual mode).

Furthermore, in the illustrated embodiment, there is a limited program (Program LIMT) automatic exposure mode, a hyper-program (Hyper Program) automatic exposure mode used as a specific program exposure mode, a hyper shutter 1 - 27 priority (Hyper EE) automatic exposure mode (lens-auto mode), and a hyper diaphragm priority (Hyper ES) automatic exposure mode.

0 The following discussion will be directed to an exposure factor calculation process in the above-mentioned exposure modes with reference to Figs. 9 through 23.

Hyper Program The hyper program exposure mode referred to herein is a mode in which the program mode, the EE automatic exposure mode and the ES automatic exposure mode are changed by optionally selecting the hyper program exposure mode, the hyper EE automatic exposure mode, or the hyper ES automatic exposure mode. Operations of Hyper-program mode the ordinary program mode a re identical to those of except that the exposure mode can be varied between the above three modes by actuating the electronic dials 17,19 or the clear button 23.

Figure 9 shows a flow chart involving the hyper program exposure mode and the ordinary program exposure mode and Fig. 10 shows a program diagram thereof.

First, the relationship between the calculating WD corresponding to the Tv value and the calculating AVD corresponding to the Av value is obtained by the following formula, in accordance with the formula at step S54.

- 28 LVD=BVD+ SVD + XVD + MND =(Bv+ 7)+ (Sv - l)+ (4- Xv) + MND =(Bv+ SvXv+ MND)+ 10 =Ev + 10 =Tv + Av+ 10 =(Tv+ 5 4/8)+ (Av + 4 4/8) =TVD+ AVI) between Tv respective and (2) arE two values Here, Ev=Bv + Sv- Xv+ MND WD=Tv + 5 4/8... (1) AVD=Av + 4 4/8... (2) From the equations (1) and and WD and between Av constants added to Tv not limited to 5 4/8 and 4 4/8 and can be any whose sum is 10. The values of 5 4/8 and 4 4/8 are selected to be approximate to each other in the embodiment. Correspondences between Tv and TV1) and between Av and AVD thus obtained are shown in Table 2 and Table 3 (pages 112 and 113), by way of example:

In the program exposure mode, the optimum calculating shutter speed WD is obtained by the following equation:

WD=3/8 WD + 4 6/8 The calculating exposure value LVD is obtained at (2), the and AVI) are and Av in relationships obtained. The equations (1) - 29 step S54. Consequently, the optimum calculating diaphragm value AU is obtained from the result of this calculation (steps S61- S78).

The equation mentioned above is obtained from the basic formula of the program line (Tv=3/8 Ev+ 3) in which M=Tv+ 5 4/8 and AVD=Av+ 4 4/8. When the optimum calculating shutter speed M and the optimum calculating diaphragm value are within the shutter capability range ot the camera body 11 (range between the calculating maximum shutter speed MMAX and the calculating minimum shutter speed MMIN) and the diaphragm capability range of the taking lens (range between the calculating diaphragm value AUMAX and the calculating diaphragm value AVDMIN), speed and the optimum the optimum calculating calculating diaphragm maintained, and the EE pulse number PN, used the diaphragm value Av of the diaphragm of the during the releasing operation, is calculated maximum minimum shutter value are to maintain taking lens (steps S62, S64 -S66, S68, S69, S72). The maximum shutter speed TVDMAX and the minimum diaphragm value AVDMIN referred to are the maximum shutter speed and the open F number, respectively.

The maximum and minimum shutter speeds TVDMAX arid TVDMIN are peculiar to the camera body 11 and are 'I'VDMAX =13 (l/8000 sec.) and TVDMIN =- 5 (30 sec.) in t lie illustrated embodiment, respectively. Consequently, as M=TV+ 5 4/8, the calculating maximum and minimum shutter speed TVDMAX and TVDMIN are represented respectively by; TVDMAX =TVMAX + 5 4/8=18 4/8 TVDMIN =TVMIN + 5 4/8=0 4/8 The calculating maximum and minimum shutter speed TUMAX and TVDMIN are stored in advance in the internal ROM 41a of the CPU 41 and are memorized at predetermined addresses of the RAM 41b during the operations.

Using the inherent maximum and minimum diaphragm values AVMAX and AVMIN and the formula (AVI)=AV+ 4 4/8), the calculating maximum and minimum diaphragm values AVDMAX and AVDMIN are represented respectively by; AVDMAX =AVMAX + 4 4/8 AVDMIN =AVMIN + 4 4/8 The maximum and minimum diaphragm values AVMAX and AVMIN are input by the communication with the taking lens at step S35 (Figure 27) and the calculating maximum and minimum diaphragm values AVDMAX and AVDMIN are stored in t heinternal RAM 41b of the CPU 41 at predetermined addresses thereof.

If the object is too bright or dark to calculate the optimum exposure factors using the above-mentioned prograin line, the following operations are carried out.

When the object is too bright:

If the calculating shutter speed TVD is larger Lhan j X t the calculating maximum shutter speed TVDMAX, the optimum calculating diaphragm value AU is calculated after the calculating shutter speed WD is replaced with the calculating maximum shutter speed WDMAX (steps S62 - S64).

If the optimum calculating diaphragm value AVD thus obtained is within the diaphragm capability range, the EL pulse number PN is obtained in accordance therewith (steps S65, S66, S68 and S72).

If the optimum calculating diaphragm value AVD is larger than the calculating maximum diaphragm value AVDMAX, the optimum calculating shutter speed WD is recalculated after the optimum calculating diaphragm value AVD i replaced with the calculating maximum diaphragm value AVDMAX (steps S65 - S68). If the recalculated calculating shutter speed WD is larger than the calculating maximum shutter speed WDMAX, it is out of the range in which optimum exposure can be obtained by any combination of the calculating shutter speed WD and the calculating diaphragm value AVD. Consequently, an Ev out-of association bit is set at 1111' to indicate that the calculating shulter speed is out of association (i.e., the allowable range), and the calculating shutter speed WD is then replaced with the calculating maximum shutter speed WDMAX to calculate Llie EE pulse number PN (steps S69 -S72). If the recalculated calculating shutter speed WD is within the shuller S - 32 capability range, since optimum exposure can be effected, the control skips steps S70 and S71 and performs the calculation of the EE pulse number PN in accordance with the optimum calculating diaphragm value AVI) (steps S69 and 72).

When the EV out-of association bit is set at "V', the shutter speed (maximum shutter speed TVMAX) and the diaphragm (maximum diaphragm value AVMAX) is indicated in the LCD display panel 69 in a flickering manner.

When the object is too dark; If the optimum calculating diaphragm value AVD is smaller than tile calculating minimum diaphragm value AVDMIN, the optimum calculating shutter speed TVD is recalculated after the calculating diaphragm value AVD is replaced with the calculating minimum diaphragm value AVDMIN. If the recalculated calculating shutter speed TV1) is within the shutter capability range, the value is held and the EE pulse number PN is set at 0, as the diaphragm is an open F number (steps S73S75, S78).

If the optimum calculating shutter speed TVD is smaller than the calculating minimum shutter speed TVDMIN, under-exposure conditions exist, and accordingly, the Ev out-of association bit is set at "P' and the calculating shutter speed TVD is replaced with the calculating minimum shutter speed TVDMIN. Thereafter, the EE pulse number PN 1 is set at 0 (steps S75- S78). TVD and AVD are storedat predetermined addresses of the RAM 41b and are utilized to control the shutter speed and diaphragm value when releasing.

When the above-mentioned operations are completed, the calculating diaphragm value AVD and the calculating shutter speed TVD are replaced with a transferring diaphragm value AVT and a transferring shutter speed 'I'VT, respectively (steps S79 and S80). The relationships between the calculating diaphragm value AVD and the transferring diaphragm value AVT and between the calculating shutter speed TVD and the transferring shutter speed WT are as follows.

TVT=WD+ 10 4/8 AVT=AVD Although WT and AW are not rounded in the above equations, WT and AW are rounded in the actual operation.

The transferring shutter speed WT and the transferring diaphragm value AVT are data of a 1/2Ev step.

Namely, when this data is transferred from the CPU 41 to IPU 43, the calculated values of a 1/8Ev step are rounded to 1/2Ev. This is because the data is used only to indicate the necessary information in the IPU 43, so that accuracy greater than a 1/2Ev step is unnecessary. Tables 2 and 3 mentioned above show indicating sections corresponding to - 34 the values of WD and AVD by way of example.

Thus, the operation of the program exposure mode is finished and the program line (diagram) shown as a solid line in Fig. 10 is obtained.

c Limited Program Exposure Mode Figure 11 shows a sub-routine of the limited program exposure (automatic exposure) mode in which a photographer can set the calculating minimum and maximum shutter speeds TVD1 and TVD2 and the calculating minimum and diaphragm values AVD1 and AVD2, respectively.

operational flow in this sub-routine is similar to the sub-routine of the program exposure mode except following points. Namely, in the sub-routine shown maximum The that of for the in Fig.

11, the calculating minimum and maximum diaphragm values AVDMIN and AWMAX are replaced with the set minimum and maximum diaphragm values AVD1 and AVD2, respectively (steps S85, S93, S86, S87), and the calculating minimum and maximum shutter speeds WDMIN and WDMAX are replaced with the set minimum and maximum shutter speeds TVD1 and TVD2, respectively (steps S95, S97, S82,S83, S89, S91). The program diagram of the limited program exposure mode is shown in Fig. 12.

The calculating minimum and maximum diaphragm values AVDMIN and AWMAX, and the calculating minimum and maximum shutter speeds TVDMIN and WDMAX are set by actuating the hold button 25 and rotating the Tv electronic dial 17 and the Av electronic dial 19 when the limited program exposure mode has been selected. The setting operation shown in the flow chart of Figs. 39C and 39D will be discussed in detail hereinafter.

llyper-EE Automatic Exposure Mode Figure 13 shows a flow chart of the hyper-shutter priority (Ilyper-EE) automatic exposure mode. The program diagram thereof is shown as a dotted- dashed line in Fig. 10.

The operation for calculating the exposure factors at the hyper-shutter priority automatic exposure mode is basically the same as the operation of the ordinary shutter priority automatic exposure mode (lensauto mode), except that the exposure mode can be changed by actuating the electronic dials 17, 19 or the clear button 23.

The hyper-EE automatic exposure mode is an EE automatic exposure mode which is compulsively selected when the hyper program exposure mode is selected and when the Tv electronic dial 17 has been actuated. Return from 1he hyper-EE automatic exposure mode to the hyper-program exposure mode is effected by the operation of the clear button 23 or the power switch, etc. The switch from the hyper-EE automatic exposure mode to the hyper-ES exposure mode is compulsively effected by the rotation of the Av electronic dial 19.

In the hyper-EE automatic exposure mode, the set shutter speed WT transferred from the IPU 43 by the data communication is read and converted to the calculating k - 37 shutter speed TVD (step S101). The relationship between the transferring shutter speed M and the calculating shutter speed TVD is as follows.

M=TVT- 10 4/8 The transferring shutter speed TVT, which is 1/2 Tv in step, is converted to the calculating shutter speed TVD, which is 1/8 Tv in step, by the above operation.

The transferring shutter speed TVT is represented by data of a 1/2Ev step and is processed upon calculating, so that the decimal place thereof is identical to that of the calculating shutter speed TVD (i.e., data which is 1/8Ev in step). Accordingly, the Tv value, which is set by the user (i. e., TVT) is set as the calculating shutter speed TVD in predetermined addresses of RAM 41b.

Thereafter, the optimum calculating diaphragm value AVI) is calculated using the calculating shutter speed TVD and the calculating exposure value LVD (step S102).

If the optimum calculating shutter speed AVD is within the diaphragm capability range, the values are held and the EE pulse number is calculated (steps S103, S104, S108- S110).

If the optimum calculating diaphragm value AVD is out of the diaphragm capability range, namely, if the object is too bright or dark, the following operations are performed. When the object is too bright:

If the optimum calculating diaphragm value AVD is greater than the calculating maximum diaphragm value AUMAX, the calculating diaphragm value AU is replaced with the calculating maximum diaphragm value AVDMAX. This replacement causes an over-exposure condition, and accordingly, the EE pulse number PN is set after the Av out- of-association bit signal is set at "111 to indicate that the optimum calculating diaphragm value AVD is out of association (steps S103, S106 S110). When the Av out-of-association bit signal is set, the number 112211, indicating the diaphragm value Av in the LCD display panel 69, flickers to indicate over-exposure.

When object is too dark:

If the optimum calculating diaphragm value AV1) is value AV13MIN, the calculating diaphragin value AVD is replaced with the calculating minimum diaphragm value AVDMIN. This causes an under-exposure condition, and accordingly, the EE pulse number PN is set at "0" after the Av out-of -association bit signal is set at "1" (steps S103 S105, S107, S108, and S110). Thus, the diagram as shown as a dotted and dashed line in Fig. 10 is obtained.

When the setting of the EE pulse number PN is finished, the calculating diaphragm value AV1) and t lie calculating shutter speed TVD are converted to tile smaller than the calculating minimum diaphragm renlacement - 39 transferring diaphragm value AW and the transferring shutter speed WT to complete the operation, respectively (steps S111 and S112).

Hyper-ES Automatic Exposure Mode An embodiment of the hyper diaphragm priority (ES) automatic exposure mode (lens-auto mode) will be explained below with reference to Figs. 10 and 16.

The basic operations in the hyper-ES automatic exposure mode are basically the same as the operation of the conventional ES automatic exposure mode (lens-auto or body-set mode).

The hyper-ES automatic exposure mode is an ES automatic exposure mode which is compulsively selected when the hyper program exposure mode is selected and when the Av electronic dial 19 has been actuated. The return from the hyper-ES automatic exposure mode to the hyper-program exposure mode is effected by the operation of the clear button 23 or the power switch, etc. The switch from the hyper-ES automatic exposure mode to the hyper-EE exposure mode is compulsively effected by the rotation of the Tv electronic dial 19.

In the hyper-ES automatic exposure mode, the set diaphragm value AW transferred from the IPU 43 by the data communication is read to convert same to the calculating - 40 diaphragm value AVD (step S131). The transferring diaphragm value AVT is identical to the calculating diaphragm value AVI) (i.e., AVI)=AM. Accordingly, the diaphragm value Av manually set by the user(i.e., AVT) is set as the calculating diaphragm value AVD at predetermined addresses of the RAM 41b.

The transferring diaphragm value AVT is represented by data which is 1/2Ev in step, and it is processed upon calculating so that the place thereof is identical to that of the calculating diaphragm value AVD (i.e., data which is 1/8Ev in step).

Thereafter, the optimum calculating shutter speed TVD is calculated using the calculating exposure value AVD and the calculating exposure value LVD (step S132).

If the optimum calculating shutter speed TVD is within the shutter capability range, the values are held and the EE pulse number is calculated in accordance with the calculating diaphragm value AVE) (steps S133, S134, S138 S140).

If the optimum calculating shutter speed TVD is out of the shutter capability range, namely, if the object too bright or dark, the following operations are performed. When the object is too bright:

If the optimum calculating shutter speed TVD is greater than the calculating maximum shutter speed TVDMAX, the calculating shutter speed TU is replaced with the calculating maximum shutter speed TUMAX. This replacement causes an over-exposure condition, and accordingly, the EE pulse number PN is set after the Tv out-of - association bit signal is set at "1'I to discriminate that the optimum calculating shutter speed TV is out of association (steps S133, S136- S140).

When the object is too dark:

If the optimum calculating shutter speed TVD is less than the calculating minimum shutter speed TVDMIN, the calculating shutter speed WD is replaced with the calculating minimum shutter speed TVDMIN. This replacement causes an under-exposure condition, and accordingly, the EE pulse number PN is set at "D" after the Tv out-of-association bit signal is set at "P' (steps S133- S135, S137, S138S140).

When the EE pulse number PN is set, the calculating diaphragm value AVD and the calculating shutter ' speed TV1) are converted to the transferring diaphragm value AVT and the transferring shutter speed TVT to complete the calculation of the exposure factors (steps S141 and S142), respectively. Thus, the diagram as shown as a dotted line in Fig. 10 is obtained.

Second llyper-EE or ES Automatic Exposure Mode The second hyper-EE or ES automatic exposure mode is an automatic exposure mode in which the priority exposure factor is modified only under the condition that the non-priority exposure factor cannot be adjusted to avoid the occurrence of under-exposure or over-exposure. Namely, unlike the above mentioned hyper-EE or hyper-ES automatic exposure modes in which a change of the priority exposure factor (i.e., diaphragm value or shutter speed having a priority) does not take place even if the object is too bright or dark, the exposure factor having a priority is when the modification of the exposure factor priority cannot be adjusted to avoid modified having no over-exposure or under-exposure.

In the second hyper-EE or ES automatic exposure mode, if the shutter speed or the diaphragm value having priority causes underexposure or overexposure, the shutter speed or the diaphragm value is modified to provide an optimum exposure (Figs. 15 and 18).

The operations in the second hyper-EE automatic exposure mode and the second hyperES automatic exposure mode will be discussed below with reference to Figs. 14 and 17, respectively.

In the second hyper-EE automatic exposure mode, the set shutter speed WT stored in the IPU 43 is read by the operation of the Tv electronic dial 17 to convert same to - 43 the calculating shutter speed TVD, so that the optimum calculating diaphragm value AU is calculated in accordance with the calculating shutter speed WD and the calculating exposure value WD (steps S121 and S122). if the optimum calculating diaphragm value AVD is within the diaphragm capability range, the control enters step S132 of the hyper-ES automatic exposure mode as can be seen in Fig.

16 (steps S123, S1,25 and S127).

If the optimum calculating diaphragm value AVD is greater than the calculating maximum diaphragm value AUMAX (i.e., if the object is too bright), the calculating diaphragm value AVD is replaced with the calculating maximum diaphragm value AVDMAX, and then the control enters step S132. Conversely, if the optimum calculating diaphragm value AVD is less than the calculating minimum diaphragm value AVDMIN (i.e., if the object is too dark), the control enters step S132 after the calculating diaphragm value AVD is replaced with the calculating minimum diaphragm value AVDMIN (steps S123, S125- S127).

In step S132 of the hyper-ES automatic exposure mode (diaphragm priority automatic exposure mode), the calculating shutter speed WD is recalculated to modify the shutter speed.

Consequently, the diagrams as shown by a solid line, a dotted line and a two-dotted and dashed line in Fig. 15 are obtained. As can be seen in Fig. 15, theoptimum exposure range is widened. This can be considered a kind of automatic exposure mode in which the shutter functions in a certain program priority automatic exposure mode exposure range.

In the second hyper-ES automatic exposure mode, the set diaphragm value AW stored in the IPU 43 is read by the operation of the Av electronic dial 17 to convert the same to the calculating diaphragm value AVD, so that the optlinum calculating shutter speed WD is calculated in accordance with the calculating diaphragm value AVD and the calculating exposure value WD (steps S151 and S152). if the optimum calculating shutter speed WD is within the shutter capability range, the values are held and the control enters step S102 of the hyper-EE automatic exposure mode in Fig. 13 (steps S153, SISS and S157).

If the optimum calculating shutter speed WD is greater than the calculating maximum shutter speed TVDMAX (i.e., if the object is too bright), the calculating shutter speed WD is replaced with the calculating maximum shutter speed WDMAX, and then, the control enters step S102 of the shutter priority automatic exposure mode.

Conversely, if the optimum calculating shutter speed WD is less than the calculating minimum shutter speed WDMIN (i.e., if the object is too dark), the control c - 45 enters step S102 after the calculating shutter speed TVD is replaced with the calculating minimum shutter speed MMIN. In step S102, the calculating diaphragm value AVD is recalculated to modify the diaphragm value (steps S103 S112).

Consequently, the diagrams as shown by a solid line, a dotted line and a two-dotted and dashed line in Fig. 18 are obtained. As can be seen in Fig. 18, the optimum exposure range is extended. This can be considered a kind of program automatic exposure mode in which the diaphragm priority automatic exposure mode functions in a certain exposure range.

Although the first and second hyper EE automatic exposure modes and the first and second hyper ES automatic exposure modes are separately explained, the operations of these modes can be performed in the same camera. Namely, 2 bit signals of the exposure mode data of the E;PROM 43c included in the IPU 43 correspond to those of the above-mentioned first and second methods in the hyper-EE and hyper-ES automatic exposure modes, respectively. The signal data is transferred to the CPU 41 by the CPU-IPU communication, so that the 2 bit signals can be determined, after the hyper-EE mode or the hyper-ES mode is detected, to switch the first or second hyper-EE and hyper-ES modes.

LA llyperManual Exposure Mode The hyper-manual exposure mode (body set mode) in which both the shutter speed and the diaphragm value can be manually set by the operation from the camera body side will be discussed below with reference to Fig. 19.

In the hyper-manual exposure mode (lensauto or body the program exposure mode set mode), a photographer can set the exposure factors by actuating the electronic dials 17 and 19. However, when the clear button 23 is turned ON, the optimum exposure factors are automatically calculated in accordance with the object brightness Bv, based on the algorithm identical to that of When the clear button 23 is turned OFF, the calculated exposure factors are replaced with those which are manually set.

In the LA hyper-manual exposure mode, both the shutter speed Tv and the diaphragm value Av can be set when the Tv and Av electronic dials 17 and 19 are actuated, respectively. Furthermore, when the clear button 23 is turned ON, the function equivalent to the program automatic exposure mode can be performed. The set shutter speed Tv and diaphragm value Av are stored in the RAM 43b of the IPU 43 at predetermined addresses thereof and are indicated in the LCD panel 69 and the indicator unit 71 within the finder.

While the clear button 23 is z turned ON, t lie 1k calculating shutter speed WD and the calculating diaphragm value AVD are calculated in accordance with the program exposure mode and the control then proceeds to step S167 (step S164).

If the clear button 23 is not turned ON, the set diaphragm value AW and the set shutter speed TVT, transferred from the 1PU 43, are converted to the calculating diaphragm value AU and the calculating shutter speed TVD, and the control then proceeds to step S167 (steps S161 - S163).

At step S167, an exposure error A Ev is calculated by the following equation which is based on the opt i flium calculating exposure value LVD, obtained from the result of the actual photometering, and the exposure value (AVD + TVD), which is obtained by the calculating diaphragm value AVD, identical to the set calculating diaphragm value, and the calculating shutter speed TVD, identical to the set calculating shutter speed:

A Ev=LVD- (AVD+ TVD) If the exposure error A Ev is within an allowable limit - 3/8 < A Ev< + 3/8), overexposure and underexposure indication bits are set to illuminate a pair of LED exposure indicating elements 71a and 71b (Fig. 42E) in the indicator unit 71 within the finder (steps S168, S170, S171).

If the exposure error A EV is greater than the allowable upper limit, only the overexposure indication bit is set to illuminate the indicating element 71a to thereby indicate over-exposure (steps S168 and S169). Conversely, if the exposure error A Ev is less than the allowable lower limit, only the underexposure indication bit is set to illuminate theindicating element 71b to thereby indicate under-exposure (steps S168, S170 and S172). Although the allowable limit of exposure error A Ev is 3/8Ev iii the illustrated embodiment, another limit may be selected.

Furthermore, the upper limit value and the lower limit value can be different from each other. It is also possible to read the latitude of the loaded film from the DX code, so that the allowable limit is determined to be identical to that of the film latitude.

Thereafter, the number PN of EE pulses is obtained from the calculating diaphragm value AVD (steps S173, S174 and S175), and the calculating diaphragm value AVD and the calculating shutter speed TVD are converted to t lie transferring diaphragm value AVT and the transferring shutter speed TVT, respectively.

When the clear button is turned OFF after being ON, the optimum exposure value in the program exposure mode is converted to the series value at steps S162 and S163, which will be discussed hereinafter, and is stored at 1 predetermined addresses of the RAM 41b with the accuracy equivalent to that of the manual mode.

As can be understood from the foregoing, since, when the clear button 23 is turned ON in the hyper-manual exposure mode, both the shutter speed Tv and the diaphragm value Av are modified to optimum values depending on the photometering data (object brightness Bv) in accordance with the program exposure mode, the optimum exposure value can be manually and quickly set by a simple operation. Although the calculation of the optimum exposure factors continues while the clear button 23 is turned ON in the above mentioned embodiment, it is possible to calculate the exposure factors and store the same in the RAM 41b only when the clear button 23 is switched from OFF to ON. In this alternative, at step S161, whether the clear button 23 is switched from OFF to ON is checked.

0 - so Second LA Hyper-manual Exposure Mode in the above mentioned embodiment, the d i aphragm value Av and the shutter speed Tv are modified to those detected by the photometering operation, in accordance with the program automatic exposure mode, when the clear button 23 is turned ON. It is possible to modify only one of the exposure factors Av and Tv to an optimum value.

Furthermore, it is also possible to set the exposure factor or factors at the rounded or system Av and Tv values instead of the optimum exposure value Ev. The rounded (or system) values referred to herein mean values having steps (accuracies) which can be manually set and obtained by rounding calculated APEX values, taking into account the step of the APEX values calculated by the CPU 41 being smaller than that of the manually set APEX Selection of the optimum value an is determined in manual select flag embodiment, as can bits are "0" and value are selected, accordance with one of the E2PROM 43c. be seen in Fig. 25, values. the rounded value bit of the hyper In the illustrated when the 0- order "111, the optimum value and the rounded respectively. Furthermore, the kind of automatic exposure mode is determined in accordance with the first and second bits of the flag. The bit data can be preset when the camera is shipped or can optionally be set and modified by a photographer.

Fig. 24 shows a flow chart of an example in which at least one of the exposure factors is modified to an optimum value and an example in which the optimum/system value selection is effected in combination, using the data of the hyper manual select flag of the E2PROM 43c within the IPU 43. The data of the E2PROM 43c is stored in the RAM 43b of the IPU 43 upon operation, and the same data is transferred to the CPU 41 also to be stored in the RAM 41b thereof by the CPU- 1PU communication.

The state of the clear button 23 is checked at step S601. If the clear button 23 is turned ON, the control proceeds to step S603 at which point the modifying mode of Tv and Av in the LA hyper-manual mode, in accordance w! th the hyper-manual select flag data, is checked. In the illustrated embodiment, the first and second bits of the hyper-manual select flag data are used. If the value represented by the 2 bits is 91019, '1111 and "2", the control.

proceeds to step S605 (program automatic exposure mode operation), step S607 (LA diaphragm priority automatic exposure mode operation), and step S609 (LA shutter priority automatic exposure mode operation), respectively.

If the value represented by the 2 bits is "3", the control proceeds to step S611 without performing the exposure mode operation. Consequently, the calculating shutter speed TVD, the calculating diaphragm value AVD, the indicating shutter 52 speed TVT, and the indicating diaphragm value AW are memorized in the RAM 41b of the CPU 41.

Thereafter, the system/optimum bits of the select flag data are checked at step S611. If the value represented by the bits is "0", the control proceeds to step S163 (system value setting operation) and if the value is Ill", the control proceeds directly to the sub-routine of the Manual-1 (optimum value setting operation).

The optimum value setting operation is the same as that of the first embodiment. The system value setting operation will be explained below. The calculation of AWD and TVTD subsequent to the operations at steps S605, S607 and S609 means that the calculating shutter speed WD (S613) and the calculating diaphragm value AVD (S615) are calculated again after the calculating optimum values AVD and WD are obtained, based on the values WT and AW which are obtained in accordance the obtained calculating optimum values AVD (=AVT) and (TVT) (by the last calculation of AWT and WDT in sub-routine of steps S605, S607 and S609). As a result, calculating optimum diaphragm values AVD and indicating optimum with WD the the the calculating optimum shutter speed WD once obtained are replaced with the calculating system diaphragm value and the calculating system shutter speed, respectively. The operations subsequent to step 167 are identical to those in the first embodiment.

In the second embodiment mentioned above, six kinds of LA hyper-manual exposure modes (control modes) below can be selected.

(D Exposure control by the optimum shutter speed Tv and the optimum diaphragm value Av which are obtained when the clear button 23 is actuated in the program automatic exposure mode (first embodiment); (2) Exposure control by the system (rounded) shutter speed Tv and the system (rounded) diaphragm value Av which are obtained when the clear button 23 is actuated in the program automatic exposure mode; C3) Exposure control by the optimum diaphragm value Av which is obtained when the clear button 23 is actuated in the shutter speed priority automatic exposure mode; C4) Exposure control by the system (rounded) diaphragm value Av which is obtained when the clear button 23 is actuated in the shutter speed priority automatic exposure mode; (s) Exposure control by the optimum shutter speed Tv which is obtained when the clear button 23 is actuated in the diaphragm priority automatic exposure mode; C6) Exposure control by the system (rounded) shutter speed Tv which is obtained when the clear button 23 is actuated in the diaphragm priority automatic exposure mode.

LM Hyper-Manual Exposure Mode The following discussion will be directed to the hyper-manual exposure mode (lens-manual mode) in which the shutter speed is set on the camera body side and the diaphragm value is set by the taking lens 65, with reference to Fig. 20.

In the LM hyper-manual exposure mode, the shutter speed Tv is manually set by adjusting the Tv electronic dial 17, but when the clear button 23 (clear switch SWCL) is turned ON, the shutter speed is automatically modified to an optimum value in accordance with the object brightness Bv.

If the clear button 23 is not turned ON, the transferring shutter speed WT (value of 1/2EV step) sent from the IPU 43 is directly converted to the calculating shutter speed WT (steps S181 and S182). Thereafter, the control proceeds to step S185.

Conversely, if the clear button 23 is turned ON, the shutter speed Tv is calculated in accordance with the lens-manual diaphragm priority (ES) automatic exposure mode which will be discussed hereinafter value which is set by the diaphragm 65 and which is input through the the A/D converter 51 by step SIS in S183). Thereafter, the selection C based on the diaphragm ring of the taking lens diaphragm volume 53 and fig. 5 (steps S181 and of the system/optillitiffl - 55 values is effected similar to the LA hyper-manual exposure mode at step S184. If the system value is selected, the calculation of TVDT is effected for the same reason as that in the LA hyper-manual exposure mode.

At step S185, the calculating diaphragm value AWRD is calculated, based on the diaphragm value Av converted to the digital value AVAID and set by the diaphragm ring of the taking lens 65 and based on the adjusting value AVadj peculiar to the camera body 11. Consequently, the exposure error A Ev is obtained by the following equation (step S186):

A Ev=LVD- WD - AWRD - MND If the exposure error A Ev is within the allowable limit, the overexposure and underexposure indication bits are set. If the exposure error A Ev is greater than the upper limit value, the overexposure indication bit data is set. and if the exposure error A Ev is less than the lower limit value, the underexposure indication bit data is set (steps S187 --S191). Thereafter, the EE pulse number PN is set to the greatest value (255 in the illustrated embodiment), and the calculating shutter speed WD is converted to the transferring shutter speed TVT. This completes the exposure factor setting operation (steps S192 and S193). The reason that the EE pulse number PN is set to the greatest value is to ensure that the stop-down - 56 mechanism of the camera body 11 is driven to an extreme stop-down position corresponding to the diaphragm value set by the diaphragm ring of the taking lens 65.

As can be seen from the foregoing, with the present invention, since the shutter speed Tv is set to the optimum value or the rounded system value obtained in the diaphragm priority automatic exposure mode when the clear button 23 is turned ON in the LM hyper-manual exposure mode, the optimum exposure value can be manually and quickly obtained by a simple operation.

LM Diaphragm Priority Automatic Exposure Mode The following discussion will be addressed to tile lensmanual diaphragm priority (ES) exposure mode in which the diaphragm is set by the diaphragm ring of the taking lens 65, with reference to Fig. 21.

The calculating diaphragm value AWRD is calculated in accordance with the converted diaphragm value AVA/D which is obtained by converting the diaphragm value Av set by the diaphragm ring of the taking lens 35, and the inherent adjusting value AVadj of the camera body 11 (step S201). Based on the AWRD value thus obtained, the calculating shutter speed WD is calculated by the following equation (step S202); WD=WD - AWRD - MND Thereafter, if the calculating shutter speed WD is within the shutter capability range, the EE pulse number PN is set to be the largest value (steps S203, S205, S208). If the calculating shutter speed WD is greater than the calculating maximum shutter speed WMAX, or less than the calculating minimum shutter speed WMIN, the calculating shutter speed WD is replaced with the calculating maximum shutter speed WMAX (steps S203 and S204), or with the calculating minimum shutter speed WMIN (steps S203, S205 and S206). Thereafter, the EE pulse number PN is set at the largest value after the Ev out-of-association bit is set (steps S207, S208).

Finally, the calculating shutter speed WD is converted to the transferring shutter speed to be transferred to the IPU 43 to thereby complete the operation (step S209).

LA, LM Bulb Exposure Mode The bulb exposure mode will be discussed below with reference to Figs. 22 and 23.

In the lens-auto bulb exposure mode, the transferring diaphragm value AW set by the Av electronic dial 19 is read through the CPU-IPU communication and converted to the calculating diaphragm value AVD (step S211). Thereafter, the EE pulse number PN corresponding lo the calculating diaphragm value AVD is S212 and S213), the underexposure indication bits are reset and calculated (steps and overexposure then, the calculating diaphragm value AVD is again converted to the transferring diaphragm value AW (steps S215 and S216). The operation is thus completed. If the calculating diaphragm value AVD is identical to the calculating minimum diaphragm value AVDMIN, the EE pulse number PN is set at "0" (steps S212, S214).

In the lensmanual bulb exposure mode, the EE pulse number PN is set at the greatest value, so that the stop-down mechanism can be driven to the diaphragm value set by the diaphragm ring of the taking lens. Thereafter, the underexposure and overexposure indication bits are reset to finish the operation.

IPU Main Routine The above explanation has been directed to the operations of the CPU 41. The main routine of the IPU 43 will be explained below (Fig. 26). The photographic data, such as the manually set diaphragm value Av and shutter speed Tv, the indicating diaphragm value Av and shutter speed Tv, the selected exposure modes, the transferring diaphragm value AW and shutter speed WT transferred through the communication between the CPU 41 and the taking lens, the maximum F number FNo, and the minimum F number FNo are stored in the internal RAM 43b of the IPU 43 at different addresses thereof.

The IPU 43 always operates when the battery is in the camera performing 1PU-MAIN shown in Fig. 26. The IPU 43 first initializes the ports thereof and the RAM 43b to carry out the initial setting of the modes (steps S220S222). Thereafter, the exposure mode is set to its initial mode. The initial mode is determined in accordance with the state of the port PLO of the 1PU 43 and is either the hyper program exposure mode or the diaphragm priority automatic exposure mode corresponding to the case of the lens-auto mode and the lens-manual mode, respectively.

Thereafter, intermittent operations are repeated by a 32ms timer (steps S223- S229-2). The IPU 43 performs the following intermittent operations. When the set time of the 32ms timer is up, the switch inputs, i.e., t lie levels of the switch input ports PCO- PB5 are successively input to the IPU 43. If the level of the ports is "L" (ON), the input operation corresponding to the switches and the determination of the type of taking lens are performed, so that the data, such as the modes set by the switches or the lens type data, etc., is written into the RAM 43b, and the lens data is input to the IPU 43 through the communication with the lens (steps S223 - S225).If the time of the 32ms 1 - 60 timer is not up, the control jumps to step S228 (steps S223 and S228).

Thereafter, whether or not the main switch SWMAIN is turned ON is checked. If the main switch is turned OFF, the Hyp-Tv flag and the Hyp-Av flag are reset to turn the power-hold OFF (i.e., turn the main power source of the CPU 41 OFF). Thereafter, the MI, mode flag is reset (i.e., hold bit is cleared), and the control is then returned to step S223 (steps S226, S226-2, S229-2). If the main switch SWMAIN is turned ON, whether or not the photometering switch SWS is turned ON is checked. If the photometering switch SWS is turned ON, which usually means the picture taking operation has already begun, the starts and the power-hold is activated 41 (steps S226, S227-1, S227-2).

control Droceeds to steD S228 photometering timer to actuate the CPU Thereafter, Conversely, if t lie photometering switch SWS is not turned ON, control skips the start of the photometering timer and the power-hold operation to step S228 (steps S226, S227-1 and S228).

In step S228, the diaphragm value (F) and the shutter speed (S-1) etc., used in the photographing operation at the selected photographic mode are indicated in the LCI) panel 69 and the indicator unit 71 within the finder. Thereafter, whether or not the set time of the photometering tinier is up is checked. If the time is up, - 61 the power-hold is inactivated and the control is then returned to step S223. Conversely, if the time is not up, the control is directly returned to step S223 (steps S229-1, S229-2, S223).

If the intermittent operation by the timer is interrupted by the communication with the CPU41, tile communication is performed. Similarly, if the electronic dials 17 and 19 are rotated, the electronic dial setting is carried out. Note that when the main switch SWMAIN is turned OFF, interruption does not occur.

c Communication with Lens The sub-routine of the communication with the lens CPU at step S225 will be described below with reference Lo Fig. 27. The CPU 43 drops the level of the pin CONT to '%'I (Logic "0"), and receives the mount pin data (open F number Fniin, the maximum F number Fmax, and Auto/Manual (A/M) data input thereto (steps S31 and S32). As disclosed in Japanese Patent Kokai (Unexamined Publication) No. 63-184719 filed in the name of the assignee of the present application, the pins of the taking lens coming into contact with the pins RES/Fmin3, SI/Fmin2, Fmaxl, Fmax2 and -SCK- /Fininl are connected to transistors, so that the maximum F number Fmax of 2 bits and the open F number Fmin of 3 bits are constituted by the levels thereof in combination depending on the ONIOFF states of the transistors. The pin A/M is connected to the A/M selection switch SWAIM, so that the diaphragm Auto/Manual data of 2 bits is constituted by the ONIOFF states of the A/M selection switch.

The CPU 41 inverts the level of the pin CONT into logic 11111 (i.e., level 111111) to determine the presence of the automatic focusing (AF) lens KAF attached to the camera body and the kind of the attached lens (steps S33 and S34). The taking lens which can be discriminated in the present invention is a manual lens K having no mount pin, an auto lens KA having the mount pins but no lens ROM, or an auto AF lens KAF having the mount pins and the lens ROM.

If the level of the pin CONT is @fill, t lie communication with the taking lens 65 is carried out and the lens data is input (steps S34 and S35). If the levels of the mount pins Fmaxl, Fmax2, Fminl, Fmin2 and Fniin3 dre all "1", and if the 5 bits representing the kind of leris are "11111", it is determined that there is a problem with the lens, and accordingly, the no lens bit NoLens is set and the control is returned (steps S36, S37 and S38). if the level of at least one of the mount pins Fmaxl - Futax2 and Fminl - Fmin3 is "0" and if the kind of lens discriminated is the AF lens KAF, the AF lens KAFLens bit is set and the control is returned (steps S36, S39 and S40).

Otherwise, whether or not the mode is the lens-auto mode or the lens-manual mode is checked. If the mode is the lens-auto, the auto lens KALens bit is set and the control is returned (steps S34- S36, S39, S41, S42).

If the mode is the lens-manual and if the levels of the pins Fmaxl and Fmax2 are "W' and the levels of the pins Fminl-Fmin3 are "11111, the no lens flag (NoLens bit) is set and control is returned, since the taking lens is not attached to the camera body (steps S43 and S44).

If the mode is the lens-manual mode and if the levels of the pins Finax 1 and Fmax2 are 'TW' and the levels of the pins Fminl- Fmin3 are "000", the lens is the manual lens K, and accordingly the manual lens flag (KLens bit) is set and the control is returned (steps S45 and S46).

Unless the levels of the pins Fmaxl Fmax2, Fininl-Fmin3 are all "V' or "0", the lens is the auto lens KALens in the lens-manual mode, and accordingly, the auto lens KAlens bit is set and the control is returned (steps S41, S43, S45 and S42).

Thus, the type of lens, the lens data, and the lens Auto/Manual data are set in the memory of the IPU 43 arid are transferred to the CPU 41.

Figure 28 shows a sub-routine of the switch input operation at step S224. If any one of the drive switch SWDRIVE, the ISO sensitivity setting switch SWISO, Lhe exposure correcting switch SW EF, and the exposure mode switch SEMODE is turned ON, the operation in the corresponding sub-routine (note: only the mode shift and MODE IN sub-routines are shown in Fig. 28) is performed (steps S231 - S233). Upon completion of the input operation, the mode shift operation, the MODE IN operation, and the memory lock operation are effected and the control is returned (steps S234 - S236). The mode shift sub-routine, the MODE IN subroutine and the memory lock sub-routine will be discussed hereinafter.

Operation of Electronic Dials Figures 29 and 30 show the sub-routines of the operations of the Tv and Av electronic dials 17 and 19. The main routine is interrupted by these sub-routines when the Tv or Av electronic dial 17 or 19 is rotated, so that any one of the ports PAO, PA1, PA2, PA3 is turned ON to set the associated Tv or Av dial change bit (steps S271, S281).

17 is rotated, t lie direction of the rotation of the Tv electronic dial 17 is checked at step S272. If the Tv electronic dial 17 is rotated in the right (clockwise) direction, the port PAO is set at "0" (the port PAl remains at 111"), the clockwise rotation bit is set, and if the Tv electronic dial 17 is rotated in the left (counterclockwise) direction, the port PAl is set at "0" (the port PAO remains at "1"), the right direction bit is reset, and then the control is returned (steps S273 and S274).

Similarly, when the Av electronic dial 19 is rotated, the Av dial change bit is set, and the right direction bit is set or reset (steps S282 S284). The electronic dial change bits and the right direction bits are used in the setting operations of the Av and Tv electronic dials 17 and 19 and the exposure mode selecting operation, etc., which will be explained below.

When the Tv electronic dial 66 - Setting of Tv, Av Electronic Dials The following discussion will be addressed to the operation of the IPU 43 in accordance with the sub-routine shown in Figs. 31 and 32 when the electronic dial 17 or 19 is actuated in a specific exposure mode.

The specific exposure mode in the illustrated embodiment is either the program mode, the limited program mode, the hyper-program mode, the EE automatic mode, the lens-auto ES automatic mode, or the manual mode.

Furthermore, in the illustrated embodiment, the shutter capacity of the camera is 30 sec. - 1/8000 sec. (Tv= - 5Tv - + 13Tv) and the diaphragm capacity is the open F number Fmin (=Avmin) read from the taking lens through the maximum F number Fmax (=Avinax). For clarification, it is assumed that Tv and Av are both 1/2Ev.

Concerning the Tv dial check, the Tv dial change bit is first checked. If the bit is "0", the control is directly returned, and if the bit is "P', whether or not the right direction rotation bit is set is checked (steps S401, S402). If the right direction rotation bit is set (i.e., the Tv electronic dial 19 is rotated in the right direction), the shutter speed Tv is increased to the maximum shutter speed Tvmax 1/2 Tv by 1/2 Tv (steps S402, S403, S404). Conversely, if the right direction rotation bit is reset (i.e., the Tv electronic dial 19 is rotated in 1 Q electronic dial 1 diaphragm value Av maximum diaphragm S414). Thereafter - 67 the left direction), the shutter speed Tv is decreased 1/2 Tv by 1/2 Tv until the minimum shutter speed Tvrnin is reached (steps S402, S405, S406). Thereafter, the Tv dial change bit is cleared and the Tv right direction rotation bit is reset (step S407).

With respect to the Av dial check, if the Av 7 is rotated in the right direction, the is increased 1/2 Av by 112 Av until the value Avmax is reached (steps S411the Av dial change bit is cleared and the Av right direction rotation bit is reset (step S418). Conversely, if the Av electronic dial 17 is rotated in the left direction, the diaphragm value Av is decreased 1/2 Av by 1/2 Av until the minimum diaphragm value Avmin is reached (steps S411, S412, S415, S416). Thereafter, the Av dial change bit is cleared and the Av right direction rotation bit is reset (step S418), and the control is returned. The sub-routines of figures 31 and 32 are called at the Tv dial set and the Av dial set, respectively, which will be discussed hereinafter.

Selection of Exposure Mode Figures 33, 34A and 34B show sub-routines of the selection or modification operation of the exposure modes. The change of the exposure modes is effected by the IPU 43 - 68 in accordance with the program memorized ROM 43a of the IPU 43.

- Mode Shift in the internal The mode shift operation is effected to convert the IPU exposure mode to the CPU exposure mode. Namely, the IPU mode which is used in the IPU 43 is converted to the CPU mode which is used in the CPU 41. Table 4 (page 114) shows a relationship between the IPU mode NO. and the CPU mode No.

In the mode shift operation (Fig. 33), the IPU 43 checks the lens diaphragm mode. If the lens diaphragm mode is a manual mode, the CPU mode is set to be the lensmanual mode (i.e., one of IPU modes LB (0- 2) is set as the CPU mode) and the control is returned (steps S621 and S623). If the hyper-Tv flag and the hyper-Av flag are both cleared in the lens-auto mode, the CPU mode corresponds to the lens-auto mode plus 8, and the -control is returned. If the hyper-Tv flag is set, the CPU mode is set at "8", and the control is returned (steps S621, S625, S629 and S631).

ModeIn The mode-in operation (step S235) is sub-routine of the SW-IN operation (step exposure mode/drive lever 29 is moved to i.e., when the exposure mode switch SWMODE during the intermittent operation by the 32 2 performed as a S224) when the the MODE side is turned ON, ms timer. The 1 variation of the exposure modes is effected by the Tv electronic dial 17 when the exposure mode/drive lever 29 is moved to the MODE side. The exposure modes corresponding to the exposure mode numbers are shown in Table 4 mentioned above.

The mode-in operation will be described below detail with reference to Figs. 34A and 34B. The and hyper-ES modes have no independent mode No. and exposure mode No. (14) which is the same as that in more hyper-EE have an of the hyper program. The hyper-EE and hyper-ES modes can be discriminated by the Hyp-TV and Hyp-Av flags, respectively.

The taking lens in the illustrated embodiment has, an auto/manual selection switch SWA/M which is actuated by the diaphragm ring thereof. When the auto/manual selection switch SWA/M is moved to the manual side, the diaphragm is set on the taking lens side. If the lens-manual mode is detected at step S241, the control proceeds to step S242 to select a desired exposure mode from among the LM diaphragm priority (ES) automatic exposure mode (exposure mode No. 2), the LM hyper-manual exposure mode (exposure mode No. 1) and the LM bulb exposure mode (exposure mode No. 0). The LM diaphragm priority automatic exposure mode (exposure mode No. 2) is the initial exposure mode.

At step S242, whether or not the mode switch SWMODE is turned ON is checked. If the mode switch SWMODE is turned ON, whether or not the Tv electronic dial 17 i actuated (i.e., the Tv dial change bit is set) is checked If there is no change, the Tv dial change bit is reset and the control then proceeds to the checking sub-routine.

If there is a dial change, the direction of rotation of the dial is checked (steps S243, S244 and S251).

When the Tv electronic dial 17 is rotated in the leftward direction (counterclockwise direction), i.e., if the riaht direction bit S is 11091, the exposure mode is switched from the LM diaphragm priority mode to the LM hyper-manual mode and the LM bulb mode in this order one by one. After the Tv dial change bit is reset, the control jumps to the check sub-routine (steps S241 - S247 and S251).

When the Tv electronic dial 17 is rotated in the right direction (the right direction bit is f9111), the exposure mode is changed in the order opposite to the above-mentioned order. After the Tv dial change bit is reset, the control jumps to the check subroutine (steps S244, S248- S251).

If the exposure mode switch SWMODE is turned OFF, or if the Tv electronicdial 17 is not actuated (the Tv dial change bit is "0"), the Tv dial change bit is reset without modifying the exposure mode, so that the control jumps to the cheek sub-routine (steps S242, S243 and S251).

z Check Sub-routine In the check sub-routine (Figure 35), if one of the NOLens bit flag, the hyper-AV flag, or the hyper-Tv flag is set, the mode indication operation is carried out after the hyper-Av flag and the hyper-Tv flag are reset. The hyper-Av flag and the hyper-Tv flag represent the AE mode.

Namely, although the hyper-EE mode and the hyper-ES mode are not included in the types of AE modes, the hyper-EE mode and the hyper-ES mode can be discriminated by the hyper-Av flag and the hyper-Tv flag, respectively.

Consequently, the hyper program No. 14 and the hyper Tv flag are set in the hyper-EE mode, and the hyper program No. 14 and the hyper Av flag are set in the hyper-ES mode, respectively.

To return the inode from the hyper-EE mode or hyper-ES mode to the respective hyper program modes, the hyper-Av flag or the hyper Tv flag is reset. The hyper-Av flag and the hyper-Tv flag are always reset in the lens-manual mode by the check sub-routine, and accordingly, when tile auto/manual selection switch SWA/M is switched from "MANUAL" to "AUTW, or when the taking lens is detached from, and again attached to the camera body, the exposure mode is initialized to be the hyper-program exposure mode.

If the taking lens is the auto-lens, and accordingly, the auto/manual selection switch SWA/M is switched to "AUTW, the exposure mode Is switched mode by mode in the order: program mode-" hyper-program mode, limited program mode- LA bulb mode- program mode. The exposure mode is indicated (steps S241, S252 - S257, S264), when the exposure mode switch SWMODE is tirned ON and. the Tv electronic dial 17 is rotated in the leftward direction.

If the Tv electronic dial 17 is rotated in the right direction, the exposure mode is changed in the order opposite to the above-mentioned order and is then indicated (steps S258 - S260 and S264).

If the taking lens is an auto-lens and if one of the exposure mode switch SWMODE or the Tv electronic dial 17 is turned OFF, exposure selection operation is not effected (steps S241, S251 - S253, S261). If the clear button 23 is not turned ON (i.e., clear switch SWCL is not turned ON), the latest exposure mode is indicated (steps S261 and S264).

If the clear button 23 is turned ON, and if the exposure mode is the hyper-EE mode or the hyper ES mode, the exposure mode. If the the hyper ES Namely, since mode is initialized to be the hyper-program exposure mode is neither the hyperEE mode nor mode, the current exposure mode is maintained.

the hyper-Tv flag or the hyper-Av flag is set when the exposure mode is the hyper-EE mode or the hyper-ES mode, the flag is reset (steps S261 and S263).

Consequently, when the photographer presses the clear button 23, the hyper-EE automatic exposure mode or hyper-ES automatic exposure mode is returned to hyper-program exposure mode.

In the exposure mode selection operation mentioned above, it is impossible to directly select the hyper-EE or hyper-ES automatic exposure mode. The selection of the hyper-EE or hyper-ES automatic exposure mode is effected by the electronic dial 17 or 19 when the hyper-program exposure mode is selected. Namely, when the electronic dial 17 or 19 is actuated at the hyper-program mode, t lie hyper-Tv flag or the hyper-Av flag is set, so that the mode can be compulsively changed to the hyperEE or hyperES Furthermore when the electronic the the program hyper-ES If the hvner-ES automatic automatic exposure mode dial 17 or 19 is actuated at the hyper-EE or hyper-ES mode, the mode can be compulsively changed to the or hyper-EE automatic exposure mode, respectively. clear button 23 is turned ON, the hyper-EE or exposure mode can be compulsively changed to the respective hyper-program exposure modes. The indication of the compulsive change of the exposure mode is performed in the exposure mode indication operation which will be discussed hereinafter.

In the illustrated embodiment, the exposure modes in the lens-auto mode and the lens-manual mode are designated with serial numbers. However, in practice, the exposure modes in the lens- auto mode and the exposure modes in the lens-manual mode are stored in the memory of the IPU 43 as separate data. Furthermore, the lens- auto/lens-manual (A/M) data, the Hyp-Tv flag and the Hyp-Av flag are separately allocated in the memory of the IPU 43, as can be seen in Fig. 36.

The exposure mode is determined in accordance with the 3bits for the lensauto mode and the Hyp-Tv or Hyp-Av flag when the auto/manual data (A/M terminal), which is switched by the diaphragm ring of the taking lens, is "AUTW, i.e., "Oil. On the other hand, when the auto/manual data (A/M terminal) is "MANUAL", i.e., "V', the exposure mode is determined in accordance with the 2-bits for the lens-manual mode.

The exposure mode data of 4-bits including both the auto exposure mode and the manual exposure mode is sent to the CPU 41. The correspondence in the exposure modes (1PU mode and CPU mode) between the IPU and CPU is shown in Table 4.

Memory Lock In the memory lock operation, the exposure value Ev is locked in the memory when the hold button 25 is pressed once and the lock is released when the hold button 25 is z pressed twice. Namely, every time the hold button 25 is turned ON and OFF, the memory lock of the exposure value Ev and the release thereof are repeated. For example, 3 bits within the memory lock flag data in the RAM 43b are employed in the memory lock operation. As can be Fig. 38, one bit is the MI, mode flag (hold bit), bit the present hold switch data, and another bit hold switch data. All of these data are cleared initial state.

The memory lock operation at step S236 is performed as follows (Fig. 37). In this operation, every time the hold switch 25 is ON and OFF, the MI, mode flag is set and reset.

First, the present hold switch data is transferred to the old hold switch data, so that the ONIOFF state of the hold switch 25 is input to the present hold switch data (steps S641 and S643). Namely, when the hold switch is turned ON and OFF, the ML mode flag is set at "0" and reset at 'll", respectively. The hold switch 25 is a normally open selfreturning type. Generally speaking, since the processing time of the microcomputer is extremely short, the memory lock sub-routines are repeated several times while the photographer actuates the hold switch 25.

Thereafter, the state of the present hold switch data is checked (step S645). Since the MI, mode flag is reset seen in another the old at the 76 when the hold switch 25 is turned OFF, the control proceeds to the memory lock indication operation. Since when Lhe hold switch 25 is turned ON, the ML mode flag is set, the control proceeds to step S647 to check the old hold switch data. Upon the first operation when the hold switch 25 is turned ON, or upon the second and subsequent operationswhen the hold switch 25 is turned OFF, the ML mode flag is reset, and accordingly, the control proceeds to step S651. Upon the second and subsequent operations when the hold switch 25 is turned ON or upon the first operation when the hold switch 25 is turned OFF, the ML mode flag is set, and accordingly, the control proceeds to step S649.

Whether or not the ML mode f lag is set is checked at step S651. If the ML mode flag is set, the flag is cleared. If the flag is cleared, the ML mode flag is set (steps S655 and S653). When the ML mode flag is set, the current exposure value Ev is stored (locked), and the power hold flag is set for 5 sec. Thereafter, the control proceeds to the ML indication operation (steps S655, S657 and S659). If the ML mode flag is cleared, the control directly proceeds to the ML indication operation (steps S651 and S653).

At step S649, whether or not the ML mode flag is set is checked. When the hold switch 25 is turned ON, the ML mode flag is set, and accordingly, the control proceeds to step S659. Conversely, when the hold switch 25 isturned e OFF, the ML mode flag is cleared, and accordingly, the control directly proceeds to the M indication operation.

In the M indication operation, the asterisked mark indication flag is cleared. If the ML mode flag is reset, the control is returned. If the ML mode flag is set, the asterisked mark indication flag is set, and then the control is returned (steps S663 and S665). When the hold switch 25 is turned off, the present ML switch data, the old ML switch data and the ML mode flag are all cleared.

Exposure Mode Indication; Mode and Set Value Modification Examples of the indication of the LCD panel 69 and the indicator unit 71 within the finder are shown side by side to the left and right, respectively, in Figs. 41A through 41F, Figs. 42A through 42H, and Figs. 43A through 43C. In Fig. 41A, all t he indicating elements crystal figures, shown.

(liquid segments) such as letters, marks, s ymbo 1 s and etc., constituting the indication information are Fig. 41B shows the indication (display) when the main switch SWMAIN is turned OFF. The other figures show various indication examples. The relationship between the exposure mode indication operation and the indication (display) will be described below with reference to Figs. 39A through 39D. The exposure mode indication operation is - 78 carried out by the IPU 43 in accordance with the program stored in the ROM 43a of the IPU 43.

When the taking lens attached to the camera body is an auto-lens, the control proceeds to step S302 from step S301 to perform the following operations.

1 c llyper-Program Exposure Mode If the hyperprogram exposure mode is set, but none of the electronic dials 17 and 19 are actuated, the hyper-program exposure mode is indicated as shown in Fig. 4213. Namely, "lly P" representing the hyper- program exposure mode, "Tv 80OW' representing the initial value (l/8000 sec.) of the shutter speed, "Av 5.C (=F5.6) representing the initial value of the diaphragm value, "22" representing the number of the photographed frames of film all appear in the LCD panel 69, and the initial values of the the shutter speed Tv and the diaphragm value Av appear in the indicator unit 71 within the finder (steps S302 through S308).

The IPU 43 reads the optimum shutter speed Tv (transferring shutter speed TVT) and the optimum diaphragm value Av (transferring diaphragm value AVT), calculated in the hyper-program exposure sub-routine by the CPU 41, power of the- CPU 41 is held (remains on) data in the RAM 43b at predetermined The transferrina provided that the and stores these addresses thereof (steps S309 and S310). shutter speed TV7' and the transferring diaphragm value AVT, stored in the RAM 43b are indicated in the LCD panel 69 and the indicator unit 71 within the finder provided that the power of the CPU 41 is held.

* When the Tv electronic dial 17 is actuated (i.e., when the Tv dial change bit is set at "1"), the hyper-Tv - 80 flag is set and the hyper-Av flag is reset thereby actuating the hyper-EE automatic exposure mode (steps S303 and S311). Thereafter, the shutter speed Tv is modified in accordance with the operation of the Tv electronic dial 17, with the modified shutter speed being stored in the RAM 43b at a predetermined address thereof and the hyper-EE automatic exposure mode and the set shutter speed Tv, etc., being indicated in the LCD panel 69 and the finder indicator unit 71, as shown in Fig. 42G (steps S312 and S313).

The initial value of the set diaphragm value Av is a value calculated at the hyper-program exposure mode or the hyper-EE exposure mode. Note that in Fig. 42G, the three quarter circle which surrounds the symbol "Tv" and the two black arrows located above the symbol Tv in the LCD panel, and the line underlining the numeral "4000" in the finder indicator unit 71 represent the feasibility of the shutter speed Tv modification by rotation of the Tv electronic dial 17.

While the power of the CPU 41 is held, the IPU 43 reads (or receives) data (AVT) corresponding to the optimum diaphragm value Av (AVD), calculated in the hyper-EE automatic exposure sub-routine, and stores the data in the RAM 43b while indicating the same in the LCD panel 69, etc. (steps S314 and S315).

When the Av electronic dial 19 is actuated (i.e., when the Av dial change bit is "1"), the hyper-Av flag is set and the hyper-Tv flag is reset thereby actuating the hyper-ES automatic exposure mode (steps S304 and S316). The diaphragm value Av is varied in accordance with the direction of rotation of the Av electronic dial 19, that the modified diaphragm value Av is stored in the RAM 43b. The hyper- ES automatic exposure mode and the modified diaphragm value Av are indicated in the LCD panel 69 and the finder indicator unit 71, as shown in Fig. 4211 (steps S317 and S318).

The initial value of the set diaphragm value Av is a value calculated in the hyperprogram exposure mode or the hyper-EE exposure mode. Note that in Fig. 4211, the three quarter circle which surrounds the symbol "Av" and the two black arrows located below the symbol "Av", in the LCD panel, and the line underlining the numeral "8.0'1 in the finder indicator unit 71, represent the feasibility of the diaphragm value Av modification by rotation of the Av electronic dial 19.

The IPU 43 reads data (TVT) corresponding to the optimum shutter speed Tv (TVD) calculated in the hyper-ES automatic exposure sub-routine and stores the data in the RAM 43b, provided that the power of the CPU 41 is held. Thestored data is indicated in the LCD panel 69 and the finder so - 82 indicator unit 71 (steps S319 and S320).

When the hyper-EE or ES automatic exposure mode is selected (i.e., when the hyper-Tv or hyper-Av flag has already been set), the IPU 43 stores the optimum transferring shutter speed TVT and the transferring diaphragm value AVT, calculated optimum in the hyperES or hyper-EE automatic exposure sub-routine by the CPU 41, into the RAM 43b and displays the same on the LCD panel 69, etc., even if neither of the electronic dials 17 or 19 are actuated. Nevertheless, the IPU 43 does not perform the modification of the diaphragm value Av or the shutter speed Tv (steps S303- S305, S313- S315 or S303S306, S319- S320).

Thus, the photographer can rotate the Tv electronic dial 17 to switch the hyper-program exposure mode to the hyper-EE automatic exposure mode and select the shutter speed Tv. Similarly, it is possible for the photographer to switch the hyper-program exposure mode to the hyper-ES automatic exposure mode and select the diaphragm value Av by rotating the Av electronic dial 19. In the illustrated embodiment, upon switching exposure modes, the optimum shutter speed or the optimum diaphragm value, calculated in the previous exposure mode, become the initial value of the exposure factor (i.e., the shutter speed or the diaphragm value) which can be set at the newly selected exposure mode. The initial value of the exposure factor, set at the newly selected exposure mode, can again be varied by the subsequent operation of the electronic dial 17 or 19. Alternatively, it is possible to adopt a control system in which the exposure factors are modified at the time the exposure mode is changed.

As can be understood from the above discussion, the mode can be switched from the hyper-EE automatic exposure mode or the hyper-ES automatic exposure mode to the hyper program exposure mode when the clear button 23 is turned ON. The change from the hyper-EE automatic exposure mod(.to the hyper-ES automatic exposure mode and vice versa can be effected by the rotation of the Av electronic dial 19 and the Tv electronic dial 19, respectively. In the illustrated embodiment, when the hyper-program exposure mode is selected, the diagrams shown at a solid line, a dotted line and a dotted and dashed line in Fig. 10 can be easily obtained by actuating the clear button 23 and the electronic dials 17 and 19, respectively.

As mentioned above with reference to the hyper Tv and Av flags are released clear button 23 is turned ON (steps Figs. 33 and 34, when either the S261- S263), the hyper-program exposure mode is selected, the main switch SWMAIN is turned OFF or the taking lens is detached from the camera body. When the main switch SWMAIN is turned on or when the taking lens is attached, the mode is returned to the initial mode, i.e., the hyper-program automatic exposure mode.

Program Exposure Mode When the ordinary program exposure mode is selected IúPgl, which represents the program exposure mode, i indicated in the LCD panel 69 (steps S301, S302, S321 S323). Furthermore, when the power hold of the CPU 41 is effected, the IPU 43 reads the communication TVT, AVT data corresponding to the the optimum shutter speed Tv and the optimum diaphragm value Av, calculated in the program exposure sub-routine, and stores the data in the RAM 43b. The data is indicated in the LCD panel 69, etc., as shown in Fig. 42A (steps S324 and S325).

Limited Program Exposure Mode In the limited program exposure mode, the photographer can modify the upper and lower limits of the shutter speed and the diaphragm value, both varying along the program diagrams, by actuating the electronic dials 17 and 19 and the hold switch 25 Selection of the 1 indicated by surrounding the mited program exposure mode is illuminating the three quarter circle symbols "Av" and "Tv", as shown in Fig. 41C S - 85 (steps S461 and S462).

When the clear switch SWCL is turned ON, the lower and upper limits TV1 and TV2 of the shutter speed and the lower and upper limits AV1 and AV2 of the diaphragm value are initialized (steps S463-1, S463-2). The initial values of the shutter speed limits and the diaphragm value limits at the limited program exposure mode in the illustrated embodiment are as follows. Namely, TV1=TVMIN=30 (sec.); TV2 =TVMAX=1/8000 (sec.), AVI=AMIN; AV2=AMAX. These initial values are set when the limited program exposure mode is selected for the first time after the battery is charged. If the clear switch SWCL is turned OFF, the control proceeds to step S464 to check the photometering switch SWS without initializing the shutter speed limits TV1 and TV2 and the diaphragm value limits AV1 and AV2. Namely, the limits set by the photographer in accordance with the following processes are initialized when the clear button 23 (clear switch SWCL) is turned ON.

When the photometering switch SWS is turned ON or when the power is held, even if the photometering SWS is turned OFF, the control proceeds to step S485 swi tch (steps S464, S4651). When the photometering switch SWS is turned OFF and when the power of the CPU 41 is held, the limit value is modified, and the control then proceeds to step S485 (steps S465-1, S465-2, S466- S486). At stepS485, - 86 whether or not the power of the CPU 41 is held is checked. If the power is held, the CPU 41 reads the optimum diaphragm value Av and the optimum shutter speed Tv calculated at the limited program exposure mode and stores the data in the RAM 43b. The data is indicated in the LCD panel 69, etc. Thereafter, the control is returned. If the power is not held, the control is directly returned (step S486).

Change of the limit values is effected as follows (step S465-2 and steps subsequent thereto).

When the Tv electronic dial 17 is actuated, the limits of the shutter speed Tv are increased or decreased in accordance with the direction of the rotaion of the Tv electronic dial 17. The limits are stored in the RAM 43b and indicated (steps S465-2, S466).

When the hold button 25 is turned ON, the upper and lower limits TV1 and TV2 of the shutter speed are set. Namely, when the hold button 25 is turned ON for the first time or an odd number of times, since the ML mode flag is set, the set Tv data is modified to the lower limit TV1 (steps S467-S470), and when the hold button 25 is turned set Tv control If the shulter ON the second time or an even number of times, the data is modified to the upper limit TV2, and the proceeds to step S485 (steps S467, S468, S469,S472). hold button 25 is not turned ON, change of the 87 speed is not effected (steps S467, S485).

On the other hand, when the Av electronic dial 19 is turned ON, the limits of the diaphragm value are changed simultaneously with the limits of the shutter speed Tv. Namely, the diaphragm value is increased or decreased in accordance with the direction of rotation of the Av electronic dial 19. The diaphragm value is consequently stored in the RAM 43b and indicated in the LCD panel 69, etc.', (steps S475, S476). If the hold button is turned for the first time or an odd number of times, since the ON M11 mode flag is set at "1", the set Av data is modified to the lower limit AV1, and when the hold button 25 is turned ON the second time or an even number of times (M1 mode flag is "0"), the set Av data is modified to the upper limit AV2, and the control proceeds to step S485 (steps S478, S479, S482).

Upon completion of the modification of the limits TV1 and TV2 and AV1 and AV2 of the shutter. speed and the diaphragm value, the CPU 41 reads the optimum shutter speed Tv and diaphragm value Av calculated in the limited program exposure mode and stores the data in the RAM 43b, provided that the power of the CPU 41 is held (steps S485, S486). The stored data is indicated in the LCD panel 69 and the indicator unit within the finder.

As can limited program diaphragm value upper or lower diaphragm limit alternative, to diaphragm limits actuated, it is S467 and S477.

be understood from the foregoing, in the exposure mode, the shutter speed and the set by the photographer are changed to the shutter speed limit and the upper or lower when the hold switch 25 is turned ON. In an change the shutter speed limits op the every time the electronic dial 17 or 19 is possible to skip the operations at steps LA ES Automatic Exposure Mode When the body-set diaphragm priority (ES) automatic exposure mode (lensauto ES automatic exposure mode) is selected, the LCD panel 69 and the indicator unit 71 within the finder are displayed as shown in Fig. 42D (steps S301, S302, S321, S461, S331-S333). When the Av electronic dial 19 is rotated, the diaphragm value Av is increased or decreased in accordance with the direction of rotation thereof, stored as the set diaphragm value Av in the RAM 43b, and indicated in the LCD panel 69, etc. When the power of the CPU 41 is held, the IPU 43 outputs the diaphragm automatic optimum priority the RAM value AVT, calculated in the diaphragm priority exposure mode, to the CPU 41 which reads thE shutter speed Tv calculated in the LA diaphragm automatic exposure sub-routine, stores the data in 43b and indicates the same in the LCD panel 69, etc. (steps S334- S338).

LA EE Automatic Exposure Mode When the shutter speed priority (EE) automatic exposure mode is selected, the display of the LCD panel 69 and the indicator unit 71 within the finder is as shown in Fig. 42C, in which the initial value (l/8000 sec.) of the shutter speed Tv appears (steps S301, S302, S321, S331, S341-- S343). When the Tv electronic dial 17 is rotated, the shutter speed Tv is increased or decreased in accordance with the direction of rotation thereof, stored as the set shutter speed Tv in the RAM 43b, and indicated in the LCD panel 69, etc. When the power of the CPU 41 is held, tile IPU 43 outputs the shutter speed TVT calculated in t lie shutter sPeed priority automatic exposure mode to the CPU 41 which reads the optimum transferring diaphragm value AVV calculated in the EE automatic exposure sub-routine, arid stores the data in the RAM 43b and indicates the same in the LCD panel 69, etc., respectively, as shown in Fig. 42C (steps S344- --S348).

HyperManual Exposure Mode In the hyper-manual exposure mode in the illustrated embodiment, the function equivalent to the calculation of the shutter speed Tv and/or the diaphragiii value Av in Lhe program exposure mode, the EE automatic exposure mode- OL the ES automatic exposure mode is achieved by actuating the clear button 23.

When the body-set hyper-manual exposure selected, the display of the LCD panel 69, etc., (steps S301, S302, S321, S461, When t lie Ev clieck mode i S is as ST31, is shown in Fig. 42E S341, S349 - S351).

performed, the shutter speed Tv and the diaphragm valtic Av which are increased or decreased in accordance with the direction of rotation of the electronic dials 17 and 19 dre set in the RAM 43b and indicated in the LC1) panel 69, elc., respectively (step S352).

If the power of the CPU 41 is Yield, the slitilL-(--r speed WT and the diaphragm value AW selected in Llic manual.

mode are output to Lhe CPU 41, which iE-a(Is t_he point LED bit calculated in the body-set- iticAjiLjiii exposure siil)-1:otitiiie, stores the- same in the RAM -131), cmd controls tile illumination (_) f the exposure elements 71a and 71b (steps S353---S360).

exposure speci f i c SLA1)- 1 oil 1 i LIC j ad i ca 111 ig LA Btilb Exposure Mode When the boely-set bulb exposure mode is selecled, display of the LC1) panel 69, etc., is as shown ill Fig. 4 (steps S301, S302,S321, S461, S331, S341, S349, S361, S362) 21-, When the Av electronic dial 19 is rotated, the dii.iplii-cigiii value Av is increased or decreased in accordance-, with the direction of rotalion of the Av electronic dial 19, stored in the RAM 43b, and indicated in the LCD panel 69 all(] tht. indicator unit 71 (steps S363 - S365).

Ill the body-set shutter priority exposure mode, diaphragm priority exposure mode, inanual exposure mode '-tild bulb exposure mode, as mentioned above, the call set Lhe shulter speed Tv and the diaphragm value Av 1jy actuating the electronic dials 17 and 19. In this case, the three quarter circle, the arrows, and the letters "I'v" Umi "AC appear ill the I.CD panel 69. Also, the shulter Tv or the diaphragm value Av is underlined, as itierit.loild(l above. Accordingly, the photographer is alerted theil Llic shutter speed Tv and the diaphragm value Av can be. manually set by actuating the electronic dials 17. and 19, respectively.

Furlherniore, when the hold button 25 is ON, t lie aslerisk ma rk of the indicating element. 71C is illuminaled in the indicator unit 71 within the finder, and accordingly, the photographer is alerted that the memory is A ocked.

Lens-Manual Mode Indication of the exl)()stire mode ill 111e 1 c 11 s --111 ' i [ 1 L 1 ' 1 1 mode, in which the diaphragm value is set on the taking lens side, is effected by the IPU 43 as follows:

LM hyper-Manual Exposure Mode Selection of the LM hyper-manual exposure mode is indicated in the LCD panel 69, etc., as shown in Fig. 43A (steps S301, S371 -S373). When the Tv electronic dial17 is rotated, the shutter speed Tv which is increased ordecreased in accordance with the direction of rotation thereof is stored in the RAM 43b as the set shutter speed Tv and indicated in the LCD panel 69 and the indicator unit 71 within the finder (steps S374- S376).

Furthermore, when the power of the CPU 41 is held, the shutter speed TVT and the diaphragm value AVT selected in the manual exposure mode are output to the CPU 41 whicli reads the exposure indication bit set in the LA maritial exposure sub-routine, stores the read data in the RAM 43b, and controls the illumination of the indicating elements 71a and 71b (steps S377 and S378). Figs. 43A, (a), (b) aild (c) designate optimum exposure, over exposure, and under exposure, respectively.

- 93 LM Manual ES Automatic Exposure Mode The lens-manual diaphragm priority (ES) automatic LCD panel 69, as shown 1n If the power of the CPU exposure mode is indicated in the Fig. 43B (steps S301, S381- S383).

41 is held, the CPU 41 reads the shutter speed WT calculated in the lens-manual ES automatic exposure sub-routine and stores the data in the RAM 43b. Tile data is indicated in the LCD panel 69, etc., and the control is returned (steps S384, S385).

LM Bulb Exposure Mode When the lens-set bulb exposure mode is selected, the shutter speed Tv is set at "B" (bulb) which is indicated in the LC1) panel 69, as shown in Fig. 43C (steps S301, S371, S381, S391, S392). Ev Checking Sub-Routine In the Ev check operation, when the hold switch 25

is turned ON, the optimum exposure value at that Lime- locked, and if the electronic dial 17 or 19 is actuated thereafter, the associated exposure factor (shutter speed or diaphragm value) is increased or decreased 1 n accordance with the direction of rotation of the electronic dial 17 or 19, and the other exposure fact-oi.

(diaphragm value or shutter speed) is decreased 0 L_ - 94 increased, respectively, to retain the locked exposure value. In the Ev checking sub-routine at step S352, every time the electronic dial 17 and 19 are rotated by one sL(-,I) when the hold button 25 is turned ON, the increment or decrement of the shutter speed Tv and the diaphragm value Av by 1/2 Tv and 1/2 Av takes place, respectively. The Ev checking sub-routine will be discussed below with reference to Fig. 40.

The RAM 43b of the IPU 43 has a hold b i L corresponding to the switching operation of the hold button 25. If the hold bit is "0", i.e., if the hold button 25 is not turned ON, the shutter speed Tv and the diaphragm value Av, which have already been set are not modified (steps S421, S437). Conversely, if the hold bit is "I", i.e., if the hold button 25 is turned ON, the following operation is perf ormed.

If Lhe Tv electronic dial 17 is rotated in tile leftward direction (counterclockwise direction) by one step or more (i.e., the Tv is decreased 1/2 is increased 1/2 Av Tv change bit is "0") theshulter sliced Tv by 1/2 Tv and the diaphragm value Av by 1/2 Av until the shutter speed Tv equal to- 5 (Tv=- 5 - 30 sec.) or the diaphragm value is equal to the maximum diaphragm value AVMAX (steps S422 S427). If the Av electronic dial 19 is rotated ill tl rightward direction (clockwise direction), Ille SCARIC is Av A t 1 operation as above is performed (steps S422, S428, S429, S424- S427).

If the Tv electronic dial 17 is rotated in the rightward direction (clockwise direction), the shutter speed Tv value Av speed Tv is Derformed is increased 1/2 Tv by 1/2 Tv and the diaphragm is decreased 1/2 Av by 1/2 Av until the shutter is equal to 13 (Tv=13- 1/8000 sec.) or the diaphragm value Av is equal to the minimum diaphragm valilu AMIN (steps S422, S423, S430 -S433). If the Av electronic dial 19 is rotated in the leftward direction (counterclockwise direction), (steps S422, decreased shutter speed Tv and the diaphragm value Av are stored in the RAM 43b and the Tv, Av change bits are vusuL (steps S434 - S437).

Thus, both the shutter speed Tv and the diaphraym value Av can be simultaneously adjusted by actuating oiie of. the electronic dials 17 or 19 while maintaining Lhe exposure value Ev constant, when the hold button 25 is turned ON after the optimum shutter speed and the- diaphi-cigm value are manually set. For instance, that the optimum shutter speed Tv and are 1/125 sec., and F8.0, in the respectively, if the hold button 25 memory is locked. Thereafter, if the same operation as above S428- S4331 The increased or on the assumption diaphragm value Av hyper-manual mod(--, is turned ON, 111C for exampl e Lhe TV - 96 electronic dial 17 is rotated by two steps, theshutler speed Tv and the diaphragm value Av are changed to 1/60 sec., and F11, respectively, while maintaining exposure at the optimum value. For comparison's sake, if tile Tv electronic dial Tv is actuated at the ordinary hyper-manual exposure mode, only the shutter speed is varied, resulting in a change in exposure value. This mode will be cancelled when the hold button is actuated again.

Second Exposure Mode Indication Operation The second exposure mode indicating operation (Figure 44) Js different from the first exposure mode indicating operation in that the exposure mode can be changed only when the electronic dials 17 or 19 are rotated by more than two steps in the hyper-program exposure mode.

When neither of the electronic dials 17 or 19 is actuated and both the hyper-Tv and hyper-Av flags are- "0" i n the lens-auto hyper-program mode (i.e., Whell thehyper-program exposure mode is selected) the display in the LCD 69 and the indicator unit 71 within the finder is a:i shown in Fig. 42B (steps S501 - S508). The transferring shutter speed WT and the transferring diaphragm value AVT, calculated by the CPU 41, are stored in the RAM 43b (steps S509, S510), provided that the power of the CPU 41 is held.

Whell the hyperEE automatic exposure lltode is selected, the control proceeds from step S505 to step S514, since the hyper-Tv flag is set. Thereafter, in steps S514 --S518, the operations similar to those in steps S311 -S31,5 are effected. On the other hand, if the hyper ES automatic exposure mode is selected, the control proceeds from ster) S506 to step S524, since the hyper-Av flag is set. Thereafter, in steps S524 -SS28, the operations similar to those in steps S316 - S320 are effected.

When the Tv electronic dial 17 or the Av electronic dial 19 is rotated, namely, when the Tv-change bit or the Av-change bit is "1", the operations in the Tv dial or Av dial checking sub-routine are effected. As can heunderstood from Ihe foregoing, in the Tv dial or Av dial checking subroutine, the exposure mode is changed only when the Tv or Av electronic dial 17 or 19 is rotated by two or more steps in the same direction.

When the Tv or Av electronic dial 17 or 19 is rotaled by one step in a predetermined direction, or when Ilie Tv 0i. Av electronic dial 17 or 19 is rotated thereafter by une step in the opposite direction, the control proceeds to step S505 (steps S503, S511, S505 or steps S503, S521, S505).

When the Tv electronic dial 17 is rotated by two steps in the same direction, the control proceeds from stel) S511 to step S512 in which, if the hyper-Tv flag is M", lite Tv dial change flag is reset to permit the mode to be changed to the hyperEE automatic exposure mode and prevent the shutter speed Tv from being changed, since the hyper-EE automatic exposure mode is not selected. Thereafter, the control proceeds to step S514 (steps S512, S513 and S514). If the hyper-Tv flag is Ill", since the hyper-EE automatic exposure mode is selected, the control proceeds directly to step S514 in which the shutter speed Tv can be adjusled (steps S512, S514).

On the other hand, when the Av electronic dial 17 is rotated by two steps in the same direction, the control proceeds from step S521 to step S522 in which, if the hyper-Av flag is "0", the Av dial change flag is reset lo permit the mode to be changed to the hyper-ES automatic exposure mode and prevent the diaphragm value Av from being changed, since the hyper-ES automatic exposure mode is not selected Thereafter, the control proceeds to step S524 (steps S521, S522, S523, S524). If the hyper-Av flag is of 1 go, since the hyper-ES automatic exposure mode is selected, the conIrol proceeds directly to step S524 ill which the diaphragm value Av can be adjusted (steps S521, S522, S524).

The Tv, Av dial check sub-routines will be discussed below with reference to steps S511 and S521 in Figs. 45 and 46. In the Tv dial check subroutine, whether or noL Llic Tv - 99 dummy flag is "I" is checked at step S551. Since the Tv dummy flag is not initially set, the Tv dummy flag is sul and the old Tv dial direction flag is replaced with the present Tv dial direction flag, and the control is then returned to step S505 (step S552). The second time through the sub-routine, if the direction of rotation of the Tv electronic dial 17 is the s ame as that of the first rotation, the Tv dial dummy flag is set and the Av dial dummy flag is reset, since the present Tv dial direction flag is identical to the old Tv dial direction flag (steps S553, S555). After that, the control proceeds to step S512.

Conversely, if the direction of the second rotation of the Tv electronic dial 17 is different from that. of the first rotation, the Tv dial dummy flag is reset and the old Tv dial direction flag i.s replaced with the pre-,;e-xit dial direction flag, since the old Tv dial direction flag is different f rom the present flag (steps S551, S5b-3, S554). After that, the control proceeds to step S505.

In the Av dial check sub-routine, whether or riot thu Av dummy flag is 11111 is checked at step S561. Since the Av dummy flag is not initially set, the Av dummy flag is set and the old Av dial direction flag is replaced with the present Av dial direction flag, and the control is then returned to step S505 (step S562). The second time- through the subroutine, it the direction of rotation of the Av - 100 electronic dial 19 is the same as that of Ille- first rotation, the Av dial dummy flag is set and the Tv dial dummy flag is reset, due to the fact that the present Av dial direction flag is identical to the old Av dial direction flag (steps S563, S565). After that, the control proceeds to step S524.

Conversely, if the direction of the second rotation of the Av electronic dial 19 is different from that of Llic the first rotation, - the Av dial dummy flag is reset and tlic old Av dial direction flag is replaced with the- present. dial direction flag, since the old Av dial direction Llcig is different f roin the present flag (steps S561, S56,3, S564). After that, I-lie control proceeds to step S505.

As can be understood f rom the above diselissioll, according to the second indication sub-routine, since thereis no change ill the exposure mode, as 10119 cl S 111c electronic dial 17 or 19 is not- rotated by iiio. Le tlicin Lwo steps, even if the electronic dial 17 or 19 is rot.citLt(i accidentally or by mistake, the mode is not changed. In an alternative embodiment, it is possible to realize a coillrol system in which mode change does no take place if Lite electronic dial 17 or 19 is successively roldled Iwice within an extremely short space of time.

- 101 - The following discussion will be directed to an embodiment in which the exposure value Ev can be locked in the lens-manual (lens-set) manual exposure mode, with reference to Figs. 47 through 51.

Figure 47 shows a plan view camera having an exposure control the present invention.

In Fig. 47, a camera body 111 has a grip portion 112. A shutter button 113 is provided on the frontal portion of the top surface of the grip portion. A Tv electronic dial 114 and an Av electronic dial 115 are provided behind the shutter button 113 and on the upper portion of the back surface of the grip portion 112, respectively.

Both the Tv electronic dial 114 and the Av electronic dial 115 are in the form of rotary dials which are rotatable in the clockwise and counterclockwise directions. When the Tv electronic dial and the Av electronic dial are rotated, the shutter speed and the diaphragm value can be changed respectively. The adjustment of the diaphragm value by the Av electronic dial 115 is effected when a diaphragm ring 117, provided in a taking lens 116, is adjusted to an automatic position (AUTO) designated by "A". When the diaphragm ring 117 is adjusted to a position other than the AUTO position, i.e., to a position corresponding to a of a single-lens reflex apparatus embodying - 102 manual exposure control mode, the adjustment of the diaphragm value is effected by rotation of the diaphragm ring 117. The diaphragm ring 117 can be locked at the position AUTO so as not to rotate, and the lock can be released by depressing an unlocking button 119.

A clear button 121 is provided on the upper portion of the back surface of the camera body 111 in the vicinity of the Av electronic dial 115. A hold button 122 is provided on the opposite side the clear button 121 with respect to a finder 118 on the back surface of the camera body ill.

A slidable exposure correction/ISO lever 123 and a slidable exposure mode/drive lever 124, both slidable from a central, neutral position in opposite directions, are provided on the upper surface of the camera body 111 and on the left side of the finder 118. A main switch 125 is provided on the upper surface of the camera body 111 and on the right side of the finder 118 and may be slidably adjusted to occupy three different positions.

Figure 48 shows a circuit diagram of a control unit of a camera system embodying the present invention.

A photometering circuit 141 is connected to a CPU 131 through an A/D converter 142 to which a diaphragm volume 143 is connected. The diaphragm volume 143, associated with the diaphragm ring 117 (Fig. 47) of the taking lens 11 - 103 - A 116, outputs a diaphragm voltage representing the diaphragm value and corresponding to the angular position of the diaphragm ring 117. The diaphragm voltage is converted to a digital value corresponding to the diaphragm value Av by the A/D converter 142. The digital value is output to the CPU 131. The CPU 131 actuates the A/D converter 142 at a predetermined time, reads the object brightness signal and the diaphragm value signal set in the taking lens 116, and converts the signals to the corresponding APEX values.

A winding motor 144 winds and rewinds the film, and a mirror motor 145 moves a mirror up and down. The operations of the motors 144 and 145 are controlled by the CPU 131 through a motor driving circuit 146.

An IPU 132 is connected to a CPU or RAM of the taking lens 116. The IPU 132 communicates with the taking lens 116 and reads lens data, such as an open F number Fmin, a maximum F number Fmax, a focal length f, etc. The taking lens 116 has a lens-auto/lens-manual selection switch 151 which is effected to switch a manual diaphragm mode to an automatic diaphragm mode and vice versa, in association with the diaphragm ring 117. The lens-auto/ lens-manual selection switch 151 is connected to the IPU 132. The IPU 132 determines the existence of the manual diaphragm mode or the automatic diaphragm mode in accordance with the signal input from the lens-auto/ 104 - lens-manual selection switch 151. The "lens-auto mode" referred to means an automatic diaphragm mode in which the diaphragm value is set on the camera body side, i.e., the stop-down of the diaphragm value continues until the diaphragm value becomes a predetermined value set in the camera body. The "lens-manual mode" referred to means a manual diaphragm mode in which the diaphragm value is manually set by the diaphragm ring 117 on the taking lens 116.

Input ports of the IPU 132 are connected to a main switch SWMAIN, a photometer switch SWS, a release switch SWR, an exposure mode switch SWMODE, a drive switch SWDRIVE, an exposure correcting switch SWEF, an ISO sensitivity setting switch SWISO, a clear switch SWCL and a hold switch SWHOLD, respectively.

132 and the connection thereof to fundamentally the same as those in embodiment.

The function of the IPU these switches are the aforementioned The main switch SWMAIN is associated with the main switch 125. The photometer switch SWS and the release switch SWR are associated with the shutter button 113. The photometer switch SWS is turned ON when the shutter button 113 is depressed by a half step. The release switch SWR is turned ON when the shutter button 15 is depressed by a full step. The exposure mode switch SWMODE and the drive switch - 105 - SWDRIVE are associated with the exposure mode/drive lever 124. The exposure correcting switch SWEF and the ISO sensitivity setting switch SWISO are associated with the exposure-correction/ISO lever 123. The clear switch SWCL and the hold switch SWHOLD, which are both normally open, are associated with the clear button 121 and the hold button 122, respectively.

The Tv electronic dial 114 and the Av electronic dial 115 are connected to the IPU 132. Each of the Tv and Av electronic dials 114 and 115 has a click-stop rotation mechanism per se known. For example, a pair of input ports PAO and PAl are in a floating state at a click-stop position, and when the Tv electronic dial 114 is rotated in a clockwise or counterclockwise direction, the level of one of the input ports first drops to "L", and then, the level of the other drops to level "L". Thereafter, the level of the input port which has dropped to level "L" prior to the other is returned to the floating state before the other. Since the order of change in the level of the input ports PAO and PAl depends on the rotation of the Tv electronic dial, the IPU 132 can discriminate the direction of the rotation based on the order of change. The same is true for the Av electronic dial 115.

The IPU 132 is connected to an LCD panel 152 which is controlled by the IPU 132 to indicate various photographic - 106 information, such as the exposure modes, the shutter speed Tv, the diaphragm value Av, the number of taken frames of a film, etc.

The operation of the embodiment shown in Fig. 47 is as follows (Figs. 49 through 51).

Figure 49 shows a flow chart of the main program.

At step S601, the initialization on the automatic exposure (AE) is effected. Namely, the data necessary for the calculation of the exposure control is read out from an E 2 PROM of the IPU 132. The control proceeds to step S603 from step S602 to check whether or not the release switch SWR has been turned ON during a time interval of 4 ms beginning at a predetermined time. If the release switch SWR has been turned ON, the releasing is carried out at step S604. If the release switch SWR has not been turned ON at step S603, or if 4 ms has not elapsed at step S602, whether or not there is a lapse of time of 100 ms from the predetermined time, corresponding to 25 4 ms cycles, is checked at step S605. If there is no lapse of 100 ms, the control is returned to step S602. Conversely, if 100 ms has elapsed, the control proceeds to step S606.

At step S606, the necessary data is sent to the CPU 131 from the IPU 132. The data includes data which, for example, represents the type of exposure modes, the exposure control modes of the taking lens 116 (lens-auto mode or lens-manual mode), etc.

At step S607, the exposure value operation, - 107 - photometering is effected to calculate (Ev) detected in the photometering based on the brightness of an object to be taken. Whether the exposure control mode of the taking lens 116 is the lensauto mode or the lens- manual mode is checked at step S608. If the mode is the lens-manual mode, the manual exposure control is effected at step S610 and if the mode is the lens-auto mode, the automatic exposure control is effected at step S611. At step S612, the indicating data for the LCD panel 152 is input from the CPU 131 to the IPU 132.

Figures 50 and 51 show a program of the manual exposure control which is carried out at step S610, i.e., the lens-manual diaphragm priority exposure mode in which the diaphragm value is set by the diaphragm ring 117 of the taking lens 116.

In the manual exposure control, as will be discussed below, the Ev value is fixed when the hold button 122 is depressed. Thereafter, when the diaphragm value is varied by the diaphragm ring 117, the shutter speed is varied in accordance with the fixed Ev value.

Before a picture is taken, as the hold button 122 is not depressed, the Ev value is not fixed. Consequently, the flag FAEL is not set at "V', the control proceeds to steps - 108 - S700, S701, S711, and S712 in this order. At step S700, the calculating diaphragm value AVVRD is first calculated, based on the diaphragm value AVA/D set by the diaphragm ring 117 and the inherent adjusting value Avadj of the camera body 111. Whether or not the hold button 122 has been depressed is checked at step S712. If the hold button has not been depressed, the control proceeds to steps S714 and S716 before ending. Although the setting operation of the shutter speed Tv is not shown in the program of Figs. 50 and 51, the operations similar to those of steps S374 through S376 in Fig. 39H are performed to set the shutter speed Tv.

Here, it is assumed that the photographer actuates the Tv electronic dial 113 and the diaphragm ring 117 to set the shutter speed and the diaphragm value, and then depresses the hold button 122 to fix the Ev value determined by the shutter speed and the diaphragm value. Thereafter, when the control enters the sub-routine shown in Figs. 50 and 51 for the first time, since the flag FAEL is not set at 11111, the control proceeds to steps S700, S701, S711, S712 and S713. At step S713, the locked Ev value LVDL speed TVD, correction the taking is obtained by adding the calculating shutter the calculating diaphragm value AVVRD andthe value MND. The correction value MND depends on lens 116. Thereafter, since the hold button 122 109 is turned ON at step S714, the control proceeds to step S715 to set the flag FAEL.

When the program is performed thereafter, the flag FAEL is set, and accordingly, the control proceeds to steps S700, S701, S702 and S703. At step S703, the locked Ev value LVDL is substituted for the calculating Ev value LVD. At step S705, the calculating diaphragm value AVVRE) and the correction value MND are subtracted from the calculating Ev value LVD to obtain the calculating shutter speed TVD.

Thereafter, at step S706, if the calculating shutter speed TVD is greater than the calculating maximum shutter speed TVDMAX, the calculating shutter speed TVD is set equal to the calculating maximum shutter speed TVDMAX at step S707. If the calculating shutter speed TV1) is less than the calculating minimum shutter speed TVDMIN at stel) S708, the calculating shutter speed TV1) is set equal to the calculating minimum shutter speed TVDMIN at step S709.

Thus, the calculating shutter speed TV1) is obtained at step S707 or S709, so that the CPU 131 controls the shutter in accordance with the shutter speed TVD.

The shutter speed TV1) is converted to the communicating shutter speed M to be sent to the IPU 132 and is indicated in the LCD panel 152.

As can be seen from the foregoing, in the embodimeril of the invention shown in Figs. 48 through 51, when the - 110 hold button 122 is depressed after the shutter speed and the diaphragm value are manually set, the exposure value determined by the shutter speed and the diaphragm value is stored. Thereafter, if the diaphragm value is varied by the rotation of the diaphragm ring 117, the shutter speed is also varied in accordance with the exposure value. Therefore, the photographer can take a picture at a desired exposure value without manually adjusting the shutter speed every time the diaphragm ring 117 is rotated.

Furthermore, if the hold button 122 is turned OFF, the control proceeds to steps S711, S714 and S716 from step S702 to reset the flag FAEL, so that the shutter speed Tv and the diaphragm value Av can be independently set.

The hold button 122 is used to f ix the exposure value not only in the manual exposure control mode but also in the automatic exposure control mode.

As can be understood from the above discussion, with to the present invention, it is not necessary for the photographer to adjust the shutter speed every time the diaphragm ring is rotated in the manual exposure control mode, thus resulting in a simple photographic operation.

- ill - 1 tat) 1 e 1 command naille o f eo 111111a 11(1 content 0 1, by t e's 0 IPU elleek communi cation cbeck witb 1 1 PC 1 CIT - 1 PU transfer 1 output all data 1 2 CPU - 1 PU transfer 2 output data for indication 5 3 INJ -CPU transfer 1 input all data 20 4 IPU -CPU t.ransfer 2 input lens data IN -CPU transfer 3 inpul switch data 1 (.3 IPU -CP11 transfer 4 input exposure mode, - 112 tab 1 e 2 Tinie(l/sec) 'F v TvT Tv D 8000 1 3 29 18 4/8 6000 12. 5 28. 5 18 4000 1 2 28 1 7 4/8 3000 11. 5 27. 5 17 2000 1 1 27 1 6 4/8 1500 10. 5 26. 5 16 1000 1 0 26 1 5 4/8 750 9. 5 25. 5 1 5 500 9 25 1 4 4/8 350 8. 5 24. 5 1 4 250 8 24 1 3 4/8 1 80 7. 5 23. 5 1 3 1 25 7 23 1 2 4/8 6. 5 22. 5 1 2 6 22 1 1 4/8 5. 5 21. 5 1 1 5 2 1 1 0 4/8 4. 5 20. 5 1 0 1 5 4 20 9 4/8 1 0 3. 5 19. 5 9 8 3 19 8 4/8 (3 2. 5 18. 5 8 4 2 18 7 4/8 3 1. 5 17. 5 7 2 1 1 7 6 4/8 0 - 7 0. 5 1 6. 5 6 0 1 6 5 4/8 ---5 -0. 5 1 5. 5 5 2 - - 1 1 5 4 4/8 3- 1. 5 1 4. 5 4 4 - 1) 14 3 4/8 6-2. 5 1 3. 5 3 8- -3 1 3 2 4/8 1 () ' -3. 5 1 2. 5 2 15--- -4 1 2 1 4/8 2 0 -4. 5 1 1. 5 1 3 0 -5 1 1 0 4/8 il - 113 - tab 1 e 3 A 0. 51-W AW) atiginen- indicalion RO. Av Aif A0 tation classi. f i(,A tion 11 11 15 4/8 38 10.5 10.5 15 32 1 () 10 14 4/8 F1 1 27 9.5 9.5 14 11 3/0 22 9 9 13 4/8 11 2/8 19 8.5 8.5 13 11 1/8 16 8 8 12 4/8 11 0/8 F-9. 5 13 7.5 7.5 12 10 7/8 11 7- 7 11 4/8 10 6/8 9. 5 6. 5 6.5 11 10 5/8 1 8 6 6 10 4/8 10 4/8 F8 6.7 5.5 5.5 10 10 3/8 5.6 5 5 9 4/8 10 2/8 4.5 4.5 4.5 9 10 1/8 4 4 4 8 4/8 10 0/8 F6. 7 3.5 3. 5 3. 5 8 9 7/8 2.8 3 3 7 4/8 9 6/8 2.5 2. 5 2. 5 7 9 5/8 2 1) 2 6 4/8 9 4/8 F5. G ú1 1.7 1 5 1. 5 6 9 3/8 1.4 1 1 5 4/8 1.2 0.5 0.5 5 1 0 4 4/8 - 114 - tab 1 e 4 exposure IPU mode No. CPU niode N in o d e. lens A' 1 ens ' B' o.

(4 1) i t) (3 b i t) (2 b i t) Program 7 5 Hyper Program 6 1 4 Program LIMIT 5 1 3 R LA 4 1 2 ITS LA 3 1 1 Olyper) Manual LA 2 () Bu 1 b LA 1 9 llyper EE - 8 Hyper ES - 7 ES I.M 2 Olyper) Manual LM 1 1 Bull) LM 0 3r

Claims

CLAIMS:

J - an exposure value exposure value determined 1. An exposure control apparatus of a camera having a manual setting means for manually and independently setting a pair of exposure factors, including a shutter speed and a diaphragm value, comprising: locking means for locking an in accordance with the exposure factors; and, an exposure factor varying means for varying one of the exposure factors, based on the locked exposure value, when the other exposure factor is varied by the associated manual setting means.
2. An exposure control apparatus 1, wherein said exposure value locking lock switch which is turned ON to lock the
3. An exposure control apparatus 2, wherein said exposure value locking exposure value, which has been locked lock switch is turned OFF.

according to claim means comprises a exposure value. according to claim means unlocks the thereby, when the
4. An exposure control apparatus according to any preceding claim, wherein said exposure value locking means locks and unlocks the exposure value every time the lock switch is turned ON and OFF, respectively.
5. An exposure control apparatus according to claim - 116 - 1, wherein said exposure value locking means comprises a lock switch for locking and holding the exposure value when the lock switch is turned ON.
6. An exposure control apparatus according to claim 1, wherein said exposure value locking means comprises a lock switch for locking and holding the exposure value when the lock switch is actuated by an odd number of operations.
7. An exposure control apparatus according to any preceding claim, wherein said exposure factors can be increased and decreased as APEX values of a predetermined step.
8. An exposure control apparatus according to claim 7, wherein when one of the shutter speed or the diaphragm value is increased or decreased by a predetermined value, said exposure factor varying means decreases or increases the other of either the diaphragm value or shutter speed by the same value when the exposure value is locked by the exposure value locking means.
9. An exposure control apparatus according to any preceding claim, wherein the camera has a camera body and a taking lens detachably attached to the camera body.
10. An exposure control apparatus according to claim 9, wherein the manual setting means for setting the shutter speed is provided in the camera body and the manual setting means for setting the diaphragm value is provided in the - 117 - taking lens.
11. An exposure control apparatus according to claim 10, wherein the camera body has a manual setting means for manually setting the diaphragm value.
12. An exposure control apparatus according to claim 10 or 11, wherein the manual setting means provided in the taking lens comprises a diaphragm ring which is rotatable between an auto position, in which the diaphragm value is set by the manual setting means provided in the camera body, and a manual position, in which the diaphragm value is set on the taking lens side.
13. An exposure control apparatus according to claim 10 or 11, wherein, when the exposure value is locked by the exposure value locking means and when the diaphragm value is varied by the manual setting means provided in the taking lens, said exposure factor varying means varies the manually set shutter speed while maintaining the locked exposure value.
14. An exposure control apparatus of a camera including two manual setting means for manually and independently setting a pair of exposure factors including a shutter speed and a diaphragm value, comprising:

an exposure value storing means for memorizing the product of the APEX values of the manually set shutter speed and diaphragm value; and, - 118 an exposure factor varying means which, when one of the exposure factors is varied by the associated manual setting means and when the product of the APEX values is stored in the exposure value storing means, varies the other exposure factor so as to make the product of the APEX values identical to the product of the APEX values of the varied exposure factors.
15. An exposure control including a manual setting shutter speed and a manual apparatus of a camera means for manually setting a setting means for manually setting a diaphragm value, comprising: an exposure value locking means for fixing an exposure value, determined in accordance with the manually set shutter speed and diaphragm value, to a constant value; and, a shutter speed varying means which, when the exposure value is fixed by the exposure value locking means, varies the shutter speed in accordance with the f ixed exposure value when the diaphragm ring is rotated to vary the diaphragm value.
16. An exposure control apparatus of a camera having manual setting means for manually and independently setting a pair of exposure factors, including a shutter speed and a diaphragm value, substantially as herein described with reference to the accompanying drawings.

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