GB2270388A - Improvements in or relating to field cameras - Google Patents

Abstract

The invention provides a field camera comprising a base 3; a front standard 2 for holding a lens; a rear standard 1 for supporting a film holder 5; a bellows 4 interconnecting the front 2 and rear 1 standards; the front 2 and rear 1 standards being arranged to fold down to give a box-like structure for transporting; characterised in that the rear standard 1 comprises a mounting assembly for removably securing the rear standard 1 to the base 3; and a film holder support assembly removably secured to the mounting assembly. The present invention thus provides cameras of a modular construction which enables mounting assemblies having different sets of movements (or no movement at all) to be used interchangeably. Moreover, the modular nature of the camera also enables a given film holder support assembly to be replaced by another such assembly having a different range of movements. <IMAGE>

Description

IMPROVEMENTS IN OR RELATING TO FIELD CAMERAS The present invention relates to a field camera of the type comprising a front standard for holding a lens panel, a rear standard for supporting a film holder and bellows linking the front and rear standards the front and rear frame standards being mounted on a base, and the distance between the front and rear frame assemblies being variable to accommodate the use of lenses of differing focal length.

Such cameras, which have conventionally been manufactured from hardwoods such as teak, walnut and mahogany, with the various moving parts formed of a metal such as brass, have been known since the last century.

Field cameras of the aforementioned type currently are used by professional photographers for use in landscape or architectural photography. In order that such cameras can be portable, they are usually provided with a mechanism for folding the front and rear standards into the base to give a more compact form for carrying.

It has been conventional to build into such cameras a variety of "movements" whereby the distance between the lens panel and film holder can be varied, and the relative angular orientations of the lens holder and film holder can be varied to accommodate varying photographic requirements. For example, the lens panel in the front standard can be provided with the facility for vertical or horizontal shift, i.e. movement up and down, or from side to side in the same plane; tilt, i.e. pivotal movement of the lens panel about a substantially horizontal axis; and swing, i.e. pivotal movement of the lens panel about an axis generally perpendicular to the axis of tilt. The rear standard may be provided with an equivalent set of movements.In addition, in order to accommodate lenses of differing focal length, the camera typically is provided with a mechanism enabling the front and rear standards to be brought closer together or moved further apart. For this purpose, the base may be provided with a sliding plate arrangement actuated by a rack and pinion mechanism.

In general, the number of movements required with any given camera will depend upon the precise nature of the work for which the camera is intended. Different photographic objectives can require the presence in the camera of different movements, and it is generally considered preferable that the camera should have the minimum number of movements necessary in order to allow the camera to perform its desired function. However, field cameras of the type describedvabove are used in a relatively specialised branch of photography and it can be uneconomical to provide a wide range of cameras each having a different range of movements. Moreover, it is also costly to manufacture cameras having the full range of movements.At present, as far as the applicant is aware, there is no field camera of the aforementioned type available which is constructed in such a way that additional movements can be added, or surplus movements removed, in response to changes in the use to which the camera is intended to be put. It is therefore an object of the invention to provide a camera of modular design which enables the conversion of a camera having one set of movements to equip it with a different set of movements, without damaging the structure of the camera.

In the first aspect therefore, the invention provides a field camera comprising a base; a front standard for holding a lens; a rear standard for supporting a film holder; a bellows interconnecting the front and rear standards; the front and rear standards being arranged to fold down to give a box-like structure for transporting; characterised in that the rear frame standard comprises a mounting assembly for removably securing the rear standard to the base; and a film holder support assembly removably secured to the mounting assembly.

The mounting assembly can be a simple spacer element or framework imparting no additional movements to the camera. As such, it can be affixedto the base by means of screws, bolts, clamps or equivalent removable securing elements.

The base can be provided with predrilled holes at predefined locations to accommodate various means for securing the mounting assembly to the base.

Alternatively, the mounting assembly can be arranged to provide one or more additional movements. For example, the base and the mounting assembly can be provided with means for providing relative movement therebetween so as to vary the distance between front and rear standards.

Such means can take the form of a rack and pinion mechanism, for example, the rack being mounted on the base and the pinion being mounted on a rotatable shaft secured to the mounting assembly. The base is advantageously provided with predrilled holes enabling a rack or racks to be secured thereto.

The mounting assembly can comprise a first mounting member provided with means for securing it to the base, and a second mounting member mounted on the first mounting member and disposed between the first mounting member and the film holder support assembly.

The first and second mounting members can be provided with means for providing relative pivotal movement therebetween. The relative pivotal movement can be, for example, movement about a substantially horizontal axis, thereby imparting to the rear standard a tilting movement.

A third and subsequent mounting member can be provided between the second mounting member and the film holder support assembly, so as to secure, removably, the second mounting member to the film holder support assembly.

The second and third members can be provided with means for enabling relative movement therebetween. For example, one of the members can be provided with lateral slots within which is located a lug or boss of the other member, thereby enabling a lateral shift movement.

The second and/or third members can also be provided with means for enabling relative movement between the said member and the film holder support assembly. For example, means can be provided enabling pivotal movement between second and/or third member and the film holder support, thereby providing a swing movement.

The mounting assembly is constructed in such a way that it can be removed easily from the base and readily disconnected from the film holder support assembly.

A modular construction is thus provided which enables mounting assemblies having different sets of movements (or no movements at all) to be used interchanaeably. Moreover, the modular nature of the camera also enables a given film holder support assembly to be replaced by another such assembly having a different range of movements.

It is preferred that the front standard is also removably secured to the base and hence a range of different front standards having different movements can be used interchangeably.

The film holder support assembly and front standard are preferably each provided with pivot means enabling them to be tilted about a generally horizontal axis and into a folded position for transporting.

In a preferred embodiment, the front standard and/or rear standard are arranged for pivotal movement towards or away from the base about a horizontal axis, the extent of movement away from the base being limited by a pivotally mounted arm provided with an elongate slot which defines a path for a locking element associated with the front or rear standard, the elongate slot being provided with a counterbored region for retaining the locking element (e.g. locking screw) so as to lock the standard at a fixed angle (e.g. 900) with respect to the base.

The film holder support assembly is preferably provided with means enabling it to be tilted about two generally horizontal pivot axesr an upper pivot axis and a lower pivot axis. Preferably the rear standard can be folded down into contact with the base for carriage, by pivotal movement about the lower pivot axis.

In one embodiment the film holder support assembly comprises a pair of generally upright supporting members having extending therebetween upper and lower generally horizontal pivot axes; a pair of pivot supports to each of which are pivotably secured, at spaced apart locations, the lower ends of first and second pivot arms, the first and second pivot arms intersecting towards their upper ends and being slideably linked together at the upper pivot axis of the supporting member; one of the first and second pivot arms being provided with means for locking the pivot arm against relative movement with respect to the upper pivot axis; the lower pivot axis of the supporting member being movable along an arcuate path defined by the pivot mounting, and being lockable at a defined position on the arcuate path; the arrangement being such that when the lower pivot axis is free to move along the arcuate path, the upright supporting members are tiltable about the upper pivot axis; and that when the first and second pivot arms are not locked against relative movement, the upright supporting members are tiltable about the lower pivot axis.

The first and second pivot arms are preferably provided with elongate slots towards their upper ends, a pivot axle defining the upper pivot axis being slideable in each slot. A counterbore can be provided at an end of one slot, within which an element associated with the pivot axle can be held fast, thereby to lock the first and second arms against relative movement.

The counterbore is preferably provided towards the upper end of the front pivot arm.

The front standard preferably comprises a gimbal arrangement in which a generally rectangular frame is mounted between two upstanding arms.so as to be pivotable about a substantially horizontal axis extending between the arms; and a lens panel holder is mounted within the rectangular frame and is pivotable about a generally vertical axis extending between the upper and lower limbs of the rectangular frame.

The invention will now be illustrated but not limited by reference to the accompanying drawings in which: Figure 1 is a side elevation of a camera in accordance with one embodiment of the invention; Figure 2 is a front elevation of the camera illustrated in Figure 1; Figure 3 is a rear elevation of the camera illustrated in Figures 1 and 2; Figure 4 is an enlarged view of a locking pivot mechanism in the embodiment of Figures 1 to 3; Figure 5 is a view from below illustrating a part of the front standard of the embodiment shown in Figures 1 to 4; Figure 6 is a partial view along line X-X in Figure 3; Figure 7 is an enlarged view of the mounting assembly shown in Figure 3; and Figure 8 is a plan view of a spacer element from the rear standard in the embodiment shown in the previous Figures.

Turning now to the accompanying drawings, it can be seen that Figure 1 illustrates a camera comprising a rear standard 1, a front standard 2, a base assembly 3, and bellows 4 extending between the rear standard and the front standard 2. The rear standard 1 has means for retaining a film holder 5 and the front standard is provided with means for retaining a lens panel upon which is mounted a lens (not shown). The camera is provided with means to enable the distance between the front and rear standards to be varied to accommodate lenses of differing focal lengths.

As shown in Figure 2, the base assembly 3 comprises a base member 100 having upstanding edge portions 102 which have extending along their length, opposed grooves 104.

Recessed into a transverse channel (shown as dotted line 106) in the base member 100 is a shaft 108 (shown as a dotted line) upon which are mounted pinion gears 110 towards either end of the shaft 108. The ends of the shaft are retained within brass journal bearings (not shown), and one end of the shaft is irrotatably secured to a knob 112 so as to be rotatable therewith. The other end of the shaft is threaded to receive knurled nut 114 which can be tightened against washer 116 to prevent rotation of the shaft.

Extending along the outer edge of the base member 100 are parallel grooves 118, the purpose of which will be apparent from the description below. Rack members 120 are secured to the upper surfaces of upstanding edge portion 102 by means of screws (not shown) set into pre-bored holes.

The base assembly 3 also comprises a sliding plate 122 which has a central circular aperture (not shown).

Extending along the entire length of either edge of the sliding plate 122 are tongue portions 124 which are configured to fit into and be slideable along grooves 10 in the base member 100. Rack members 126 are secured (e.g. by screws) to the undersides of the sliding plate 122 and these engage pinions 110 thereby enabling the sliding plate 122 to be advanced back and forth along the groove 104 by rotating the knob 112.

Towards the front end of the sliding plate 122 are lever arm locking screws 128 which are screwed into threaded seats set into the sliding plate 122.

The locking screws 128 serve as a means for mounting the front standard 2 on the sliding plate 122.

As can be seen from Figure 2, front standard 2 comprises a lower frame member 130 provided with elongate slots (not shown) through which the locking screws 128 pass. By virtue of the elongate slots, the lower frame member 130 and in fact the whole of the front standard 2 can be shifted laterally with respect to the sliding plate 122.

Lower frame member 130 has integrally formed upstanding end portions 132 which are generally perpendicular to the sliding plate 122. Pivotably linked to the upstanding end portions 132 are elongate arms 134 which each have slots 136 extending from about the mid point of the arm to the top thereof.

An arm 138 is pivotably linked to the upstanding end portion 132. Arm 138 is provided with an elongate slot 140 through which passes a threaded post 142 secured to and -extending outwardly from the arm 134. A knurled nut 144 sits about the end of the threaded post 142 and can be tightened against arm 138 to fix the arm 134 in a desired angular orientation. Arm 138 is also provided with a counterbore 146 of a size just large enough to accommodate a shoulder 148 on the nut 144. The counterbore 146 is positioned such that when the shoulder 148 of the nut 144 is secured tightly into the counterbore 146, the arm 138 is locked at an angle of 900 with respect to the sliding plate 122.

Pivotably linked to, and held between, the arms 138 is a gimbal arrangement comprising a generally rectangular frame member 150 to which are secured angular adjustment plates 152. Angular adjustment plates 152 each have an arcuate slot 154, the arc of which extends through about 180 to 270 degrees (e.g. about 2100 ) . Plate 152 is pivotable about pivot mounting 154 which is slideably located within the slots 136. A locking nut arrangement 156 comprising a threaded shaft, which passes through slots 136, a plastics washer and knurled nut, enable the plate 152 (and hence the frame member 152) to be held in a desired fixed angular orientation.Metal strips 158, generally flush with the angular adjustment plates 152 are screwed to the rectangular frame member 150 and the strips are provided with shallow ribs (not shown) which protrude about 0.75 mm from the surface thereof. The ribs complement shallow recesses (not shown) in the arm 134, and provide a means of locating the rectangular frame member 150 in precise alignment with the arm 134. In order to disengage the rib on the rectangular frame member from the shallow recesses, the locking nut arrangement 156 is loosened and the rectangular frame member pulled out such that the shaft of the locking member moves along the slot 138. The arms 138 can then be gently prised apart to release the shallow rib from the groove and allow rotation of the rectangular frame 150.

The rectangular frame 150 has pivotably mounted therein by means of pivots 160, 162 a lens panel holder 164. Lens panel holder 164 is provided on its rear surface with a recess 160 within which can be held a lens panel to which is affixed a lens system (not shown). The lens panel is held in place by means of a tongue 168 and sliding catches 170.

The lens panel holder 164 is pivotable through about 300 in either direction and can be locked in a desired angular orientation as illustrated in Figure 5 and as described below. Thus the lens panel holder 164 has two pivot mountings 172 set into its edge and pivot arms 174 are pivotably mounted on the pivot mountings 172. The other ends of pivot arms 174 are provided with threaded posts 176 which extend through and are slideable along slots 178 in the rectangular frame member 150. A locking nut 180 is provided to lock the posts 176 at a given location in the slots 178 thereby fixing the angle of swing of the rectangular frame member 150 with respect to the lens holder 164.

It will be understood from the foregoing description that the front standard is provided with two tilting movements, swinging movement about an axis perpendicular to the tilt axes, and the ability to shift the lens panel sideways or up and down. Furthermore, the front standard is removable, and could be replaced by a standard having a smaller or greater range of movements.

The rear standard 1 will now be described by particular reference to Figures 1, 3, 4 and 6.

The rear standard comprises a film holder support assembly, generally designated 300, and a mounting assembly. generally designated 302.

The film holder support assembly 300 comprises a base slate member 304 having upstanding integral side plates 306. As can be seen from Figure 6, base plate 304 is provided with two pairs of arcuate slots 308 and 310, each slot of a pair being space equidistantly from a pivot arrangement formed by boss 312 on the underlying spacer plate 314 which mates with a hole 316 in the base plate 304. The spacer plate 314, described in more detail below, is provided with drilled and internally threaded bosses 318 which locate in the arcuate slots 308. Locking screws 320 provided with lever arms 322 for ease of action, provide a means firstly of securing base plate member 304 to the underlying spacer plate 314 and secondly of locking the base plate member 304 in a given angular orientation with respect to the space plate 314.This arrangement provides the rear standard with a "swing" movement.

The upstanding side plates 306 are each fitted with a pair of slotted pivot arms 324 and 326, which are pivotably linked to side plate 306 at locations 328 and 330; front arm 324 being mounted to the outer surface of side plate 306 and rear arm 326 being mounted to the inner surface thereof. PTFE or polyacetal spacers or washers are interposed between arms 324 and 326 and the relevant surfaces of the side plates 306.

Arm 324 is provided at the upper end of the slot 325 with a counterbore 327, of a size which accommodates the shoulder 336 of mounting screw 338. Mounting screws 338 n engage threaded inserts set into the wall of a film holder support frame 342, thereby securing the film holder support frame 342 to the arms 324 and 326.

Side plates 306 are also provided with arcuate slots 348, which have a counterbored recess 350 at about the mid point of the arc. Counterbore 350 is of a size to accommodate the shoulder 352 of a locking screw 354 which co-operates with a threaded insert (not shown) in the film holder support frame 342 at location 356 to provide a means of locking the support frame 342 in a particular angle of tilt about the pivot point defined by mounting screws 338.

As will be appreciated from the foregoing description, the film holder support assembly is provided with a facility for a "swing" movement as well as pivotal movement ("tilt") about two horizontal axes.

The pivot arm arrangement illustrated in Figure 4 represents an especially advantageous feature of the invention.

When the shoulder 336 on locking screw 338 is aligned with and screwed into counterbore 327, and the locking screw 354 is loosened so that shoulder 352 disengages from counterbore 350, the film holder support 342 can tilt about its upper horizontal pivot axis through an angle defined by the length of the arcuate slot 348.

Conversely, if locking screw 338 is loosened to disengage shoulder 336 from counterbore 327, and locking screw 354 is tightened such that shoulder 352 is held in counterbore 350, the frame 342 can then tilt by pivotal movement about the lower horizontal pivot axis.

The film holder support frame 342 is of generally square configuration and can be formed from a suitable wood, metal or plastics material. For example, it can be formed of a hard wood such as teak or mahogany or a composite material such as medium density fibreboard.

Alternatively, it can be moulded from a suitable plastics material such as polypropylene. Film holder support frame 342 is provided with a rebate 358 extending around the rear inner edge within which can be mounted a film holder 5 of conventional construction. Tongues 360, which may be fixed to the frame 342 by means of screws, and sliding catches 362, provide a means of retaining the film holder 5 in place.

Turning now to the mounting assembly 302; shown in enlarged form in Figure 7, in its simplest form this can take the form simply of a bracket or spacer assembly having no moving parts. However, in the embodiment illustrated, the mounting assembly is provided with means for imparting tilting movement, swing and lateral sliding movement as well as means for engaging the rack 120 on base member 100 to enable the entire rear standard to be moved backwards or forwards along the base member 100.

Accordingly, in this embodiment, mounting assembly 302 comprises a lower mounting member 400 having integral downwardly depending side portions 402. On the inner surfaces of the lower part of the side portions 402 are elongate ribs 404 for engaging and sliding along external grooves 118 on the bas member 100. Side portions 402 are also provided with pairs of aligned apertures 406 and 408 through which extend transverse shafts 410 and 412 respectively. The forward shaft 410 is threaded at both ends to receive on one end knurled nut 414 and locking nut 416, and on the other end knurled nut 420, a plurality of compressible spacers or washers 422 and locking nut 424.

The rear shaft 412 is provided with pinions 426 which engage rack 120 on the base member to enable the rear standard to be advanced along the base member when knurled knob 428, which is irrotatably secured at one end of the shaft 412, is rotated. At its other end, shaft 412 is threaded to receive an assembly comprising spacers, a knurled nut 432, and locking nut 434 which enable the shaft to be locked against rotation.

Mounted on lower mounting member 400 is intermediate mounting member 436 which has depending side portions 438.

Side portions 438 have apertures 440 and 442 therein which are aligned with apertures 406 and 408 and also receive the shaft 410 and 412 respectively. The forward aperture 440 is in the form of an arcuate slot and enables intermediate mounting member 436 to be tilted about the pivot point defined by shaft 412 and apertures 408.

Locking nuts 414, 416, 20 and 424 enable intermediate mounting member 436 to be locked at a defined angle of tilt.

Secured to the upper portion of intermediate mounting member 436 is the spacer plate 314, the construction of which is illustrated in more detail in Figure 8. The spacer plate 314 is provided along ss short portion of each side with a rebate or tongue portion 442 which is slideably located under guides 444 secured (e.g. by screws) to the upper surface of intermediate mounting member 436. The spacer plate 314 is also provided on its lower surface with drilled and internally threaded bosses 446 which locate and are slideable in transverse slots 448 in intermediate mounting member 436. Locking screws 450 with lever arms 452 enable the bosses to be locked at a given position along the length of the slots 448. The bosses 446, slots 448 and locking screw arrangement 450, 452 provide the rear standard 1 with the facility for a lateral shift movement.

The camera illustrated in Figures 1 to 8 can readily be folded into a more compact form for transporting. This is achieved by loosening the locking screws 156 and folding the front standard about pivot axis 144 in towards the base 3. The locking screws 338 on the rear standard are then loosened, and the rear standard is folded about the lower pivot axis 354 on the film holder support assembly such that the inner edge of the frame 342 abuts against the upper surface of side portions 102 of the base member 100. The camera can then be locked in the folded condition by re-tightening locking screws 338.

It will be understood from the foregoing description that the illustrated camera is composed of a number of interchangeable modular units, namely the base 3, front standard 2, film holder support assembly 300 and mounting assembly 302. Each may be varied to provide a camera having different sets of movements. Thus, a wide range of interchangeable camera types can be provided based upon a relatively small number of modular units. The invention contemplates the provision of such a range of cameras.

It will be readily apparent that numerous modifications and alterations can be made to the specific embodiments illustrated in the accompanying drawings without departing from the principles underlying the invention and all such modifications and alterations are intended to be embraced by the application.

Claims (19)

1. A camera comprising a base; a front standard for holding a lens; a rear standard for supporting a film holder; a bellows interconnecting the front and rear standards; wherein the rear standard comprises a mounting assembly for removably securing the rear standard to the base; and a film holder support assembly removably secured to the mounting assembly.

2. A camera comprising a base; a front standard for holding a lens; a rear standard for supporting a film holder; a bellows interconnecting the front and rear standards; the front and rear standards being arranged to fold down to give a box-like structure for transporting; characterised in that the rear standard comprises a mounting assembly for removably securing the rear standard to the base; and a film holder support assembly removably secured to the mounting assembly.

3. A camera according to Claim 1 or Claim 2 wherein the mounting assembly is a spacer element or framework imparting no additional movements to the camera.

4. A camera according to Claim I or Claim 2 wherein the mounting assembly is arranged to provide one or more additional movements.

5. A camera according to any one of the preceding Claims comprising a first mounting member provided with means for securing it to the base, and a second mounting member mounted on the first mounting member and disposed between the first mounting member and the film holder support assembly.

6. A camera according to Claim 5 wherein the first and second mounting members are provided with means for providing relative pivotal movement therebetween.

7. A camera according to Claim 5 or Claim 6 wherein a third mounting member is provided between the second mounting member and the film holder support assembly, so as to secure, removably, the second mounting member to the film holder support assembly.

8. A camera according to Claim 7 wherein the second and third members are provided with means for enabling relative movement therebetween.

9. A camera according to Claim 7 or Claim 8 wherein the second and/or third members are provided with means for enabling relative movement between the said member and the film holder support assembly.

10. A camera according to any one of the preceding Claims wherein the film holder support assembly and front standard are each provided with pivot means enabling them to be tilted about a generally horizontal axis and into a folding position for transporting.

11. A camera according to any of of the preceding Claims wherein the front standard and/or rear standard are arranged for pivotal movement towards or away from the base about a horizontal axis, the extent of movement away from the base being limited by a pivotally mounted arm provided with an elongate slot which defines a path for a locking element associated with the front or rear standard, the elongate slot being provided with a counterbore region for retaining the locking element so as to lock the standard at a fixed angle with respect to the base.

12. A camera according to any one of the preceding Claims wherein the film holder support assembly is provided with means enabling it to be tilted about two generally horizontal pivot axes, an upper pivot axis and a lower pivot axis.

13. A film holder support assembly according to Claim 12 wherein the rear standard can be folded down into contact with the base or carriage, by pivotal movement about the lower pivot axis.

14. A camera according to any one of the preceding Claims wherein the film holder support assembly comprises a pair of generally upright supporting members having extending therebetween upper and lower gnerally horizontal pivot axes; a pair of pivot supports to each of which are pivotably secured, at spaced apart locations, the lower ends of first and second pivot arms, the first and second pivot arms intersecting towards their upper ends and being slideably linked together at the upper pivot axis of the supporting member; one of the first and second pivot arms being provided with means for locking the pivot arm against relative movement with respect to the upper pivot axis; the lower pivot axis of the supporting member being movable along an arcuate path defined by the pivot mounting, and being lockable at a defined position on the arcuate path; the arrangement being such that when the lower pivot axis is free to move along the arcuate path, the upright supporting members are tiltable about the upper pivot axis; and that when the first and second pivot arms are not locked against relative movement, the upright supporting members are tiltable about the lower pivot axis.

15. A camera according to Claim 14 wherein the first and second pivot arms are provided with elongate slots towards their upper ends, a pivot axle defining the upper pivot axis being slideable in each slot.

16. A camera according to Claim 15 wherein a counterbore is provided at an end of one slot, within which an element associated with the pivot axle can be held fast, thereby to lock the first and second arms against relative movement.

17. A camera according to Claim 16 wherein the counterbore is provided towards the upper end of the front pivot arm.

18. A camera according to any one of the preceding Claims wherein the front standard comprises a gimbal arrangement in which a generally rectangular frame is mounted between two upstanding arms so as to be pivotable about a substantially horizontal axis extending between the arms; and a lens panel holder is mounted within the rectangular frame and is pivotable about a generally vertical axis extending between the upper and lower limbs of the rectangular frame.

19. A camera substantially as described herein with reference to the accompanying drawings.