CA2961353A1 - Film tlr camera conversion to digital tlr camera - Google Patents

Abstract

The invention provides an improved way of converting a Twin Lens Reflex (TLR) film camera into a Digital Twin Lens Reflex (D-TLR) camera, by using an assembly combination of a digital sensor (CCD or CMOS), a minicomputer, a Wi-Fi signal transmitter, optical focal lens adapter, and a power bank, all interconnected with the film TLR camera. The above components, together with wireless technologies make the film camera capable of providing input for digital imagery. The film camera's electrical and optical input does the synchronization of the film camera with the digital sensor, hence its readiness for capturing digital images.

Description

Background Of The Invention Image sensors are currently largely used for various digital cameras, but they are rarely used for the film Twin Lens Reflex (TLR) cameras. Historically, the first digital cameras added to the Single Lens Reflex (SLR) film camera body a separate assembly attached on the back, which contained a digital sensor and electronics for processing the sensor input. Typical, only SLR film cameras were used to develop digital cameras, particularly the Digital Single Reflex Cameras (D-SLR). Another segment market is for a digital back, commonly used for medium format cameras, and due to the sensor size and the technologies involved, those are extremely expensive.
Considering the advancements in microelectronics, the smaller sized camera sensors are now more affordable. Nowadays, technologies allow the insertion of an imagine capturing system (hardware, sensor and power assemblies) inside of a vintage camera without the need for physical alteration of the camera itself. This allows converting a film camera into a virtual digital camera, combining the characteristics and capabilities of the mirrorless cameras with the digital backs. The current patent presents another improved way to perform this conversion.
The relevant related technologies are shown in the following United States of America, Canada and Japan patents:
US 6365950 B1 II-Young Sohn US 4977584 A Akiyoshi Kohno, Atsushi Mikoshiba US 3356858 A F.M. Wanlass US 696788 A Clile C Allen US 2495355 A Stahl Rodolphe US 2644381 A Mendelsohn Samuel US 2766658 A Gerhard Schwesinger US 2967471 A Sommermeyer Friedrich US 2990756 A Richard Weiss US 3067664 A George H Winslow US 3143052 A Prochnow Claus, Weiss Richard US 4704023 A Kenneth J. Curran 2012-242615 Nikon US 20070122146 Al Jim Ryu US 20080079830 Al Gerald Lepage US 20120218450 Al Prebesh Pavithran, Yeow Thiam Ooi, How Chyn Cheng, Hung Khin Wong, Khen Ming Goh

2 US 20130308047 Chun-Ming Chen, Di Wu US 20140014818 Al Young Sung CHO, Dong Jae Lee, Tae Chan Kim, Tomer Livneh US 201500042843 Al lkizyan, Ike Aret; Sorek, Noam CA2888327 Al Sandu Baciu CA2887534 Al Sandu Baciu CA 2901030 Sandu Baciu Summary Of The Invention This invention presents an improved method that combines the old film camera's design with new digital sensors and electronic assemblies. The assembly can be inserted inside of a film TLR camera without performing modifications to the film camera body itself. By using the basic optical and electric signals of a vintage TLR film camera, one acquires a digital image with the similar visual properties as one would achieve by using the traditional film process. It will require the use of the film camera's flash triggering signal on several modes (M, X or other), optical adapter, and wireless Wi-Fi signal transmission to a digital sensor with a corresponding hardware module, and a power bank supply. The image signal is optically scaled and captured by a smaller (and affordable) digital sensor and processed by the hardware module.
The image data is saved on a SD card or is wirelessly transferred to an app that has several image processing and online data sharing capabilities.
Detailed Description Of The Invention The current patent design of the assembly of devices for a TLR film camera is detailed and furthermore, the functions are explained, presenting the process that results in a digital image from a film camera. The way in which the above objective for the overall assembly is achieved is best explained with reference to Figure 1 and Figure 2.
In Figure 1, a common film TLR camera 1 inner part allows the space for an assembly of several device components: a power bank device enclosure 2 inside of the film housing 3 of the TLR camera 1, a sensor assembly 4 with data capturing processor hardware 5, a module frame support 10 and an optical adjustment lens 11, and additional other optional components. All are to be placed inside the TLR film camera body, including the bottom and the back of the TLR, which currently is shown with the film back cover 6 open.

3 Using the film camera optical assembly taking lenses 7 that is brought into focus by adjusting the focus knob 8 does the capturing of the desired optical image on film. The photographer can observe the imagine from the view lens through the viewer 9.
In order to capture the perfect picture, several camera settings are defined by the photographer on a film camera (in the manual mode): the aperture, the shutter speed, the film sensitivity, and the flash mode (when is used) and focus on the subject, all those should be done prior to the push /'click' of the shutter trigger.
This is how any film TLR camera works.
For transferring the film lenses optical signal to the image capturing devices assembly the same instructions for taking a film photography are followed by photographer:
define aperture, shutter speed, sensor sensitivity (ISO), flash signal, and adjust the focus. This is characteristic to the manual mode, and the camera sensor will be setup to have similar features that will match. Since the camera sensor is not placed on the same focal plane of the film TLR camera, an optical adjustment is required to bring the film camera focal plane to the digital sensor focal plane, hence the use of optical adjustment lens assembly 11, generally as a convex lens and a support ring that gets attached to the back of taking lens assembly of the film TLR camera. The adjustment lens assembly design is directly dependent of the type of taking lens assemblies that are mounted on the camera. Varying by manufacturer it is typically expected to be a triplet lenses with 3 single lens elements in 3 groups (Cooke type), or as 4 elements in 3 groups with rear lenses conjunct (Tessar type), or other variations. The use of a general-purpose adjustment lens assembly 11 is possible, but several optical distortions and chromatic aberrations are possible to be shown on the final image if there are no post-process image corrections used by the photographer.
The flash signal on a classic film TLR camera will have the option to sync with the different types of the flash that were available between early 1920's to late 1980's, most commonly being the bulb flash (which use the setting 'M') or electronic flash (Xenon, that use the setting 'X'). Those have various milliseconds delays for the burn start prior to the pick of the shutter opening. Considering this originally designed delay, with the potential delay incurred due to Wi-Fi signal transmission, and the sensor type, the camera sensor will be adjusted for the perfect synchronization.
Once the set-up is performed on the camera, a similar set-up is done in an app that is in sync with the electronic assembly inside of the camera. Once the shutter is released the signal for the sensor is released via flash signal to Wi-Fi transmitter 12, and the optical signal (light) is captured by the sensor 4 on its focal plane through the optical

4 adjustment 11, and then processed by the data processing unit 5, filtered and refined, and ultimately gets stored on a micro-SD as a image data file, or wirelessly shared/saved on a network, at the users preference.
The minimum requirements for the entire assembly to work comprise of: a power source 2, hardware electronics including the sensor 4 and data processing unit

5, a flash signal Wi-Fi transmitter 12 (with its own battery power source), optical adjustment of the film plane, a synchronizing system or an app (D-TLRs app), and a wireless connection to a network. The resulting in-camera assembly provides digital imagery that can be shared wirelessly to other devices or through the media sharing services.
The basic optics characteristics of the TLR camera are set-up by the photographer and with the help of the app the settings are synchronized with the camera sensor.

The film TLR cameras are typically known as 6x6 cm cameras, which used 120 film roll.
A smaller size version was produced using 4x4 cm format (examples being 'Baby' Rolleiflex or Yashica 44), which used 127 film roll. Since the current patent is using a small size camera sensor as part of the assembly, it can be utilized for these smaller film TLR cameras as well, by employing a modular support frame 10. The support frame 10 can be inserted inside a 6x6 cm camera and the electronics (camera sensor, processor) placed on a 4x4 cm frame that corresponds to the smaller 4x4 cm film TLR
camera. That will result in a multipurpose utilization of the overall digital assembly, for various film formats.
Figure 2 presents the typical section of a vintage film TLR camera with the assembly of electronics placed inside the camera. The original design of a film TLR camera will have the optical imagine projected at the back of the camera, on the film plane with a square medium format film height (H), where the film roll is placed. Once the optical adapter 11 is placed inside of the film camera 1, the focal plane is changed closer to the lenses, at the sensor camera plane location, at a new distance (F) from the original film plane location. In addition, the optical projected image dimensions are proportionally smaller, maintaining the square format but with a new format height (h).
The advantage of the use of this configuration is that the camera sensor dimensions are smaller compared to the option of using a larger sensor for the original TLR camera film plane, as currently performed by digital backs, hence a substantial cost saving of the camera sensor type that can be used.
The power bank 2 is connected to the microcomputer or processor 5 that is processing the image captured by the sensor 4, and is rechargeable. The sensor module is comprised of: the image sensor 4 with a microcomputer and a processor chip 5 that is prone to produce heat. In order to dissipate the heat, a heat sink component 13 is placed at the back of the camera, which is in contact with the film pressure plate 14, usually mounted on the inner side of the film back cover 6 of the camera.
Considering this configuration the potential heat generated by the electronic parts is dissipated at the back of the film TLR camera, minimizing the potential optical distortions due to various air temperatures inside the camera body. Utilizing the existing components of the film camera, that had the film functions and are readapted for digital and electronic support functions, will solve the issue.
The modular components, like the camera sensor 4 and microcomputer 5, are independent from the general assembly and can be changed by the users over time once upgrades (and updates) are performed. That can include, but is not limited to, an increase in RAM for processing the data, GPS capabilities for location data acquisition, Wi-Fi to local or private networks, wireless synchronization to shutter release by link to flash release input signal or other potential enhancements of the system.
Additional independent microcomputers can be added that will work in sync with the data imagine processing unit 5. All those electronics can link wirelessly to an app that controls the camera sensor functions and capabilities, as a camera control module. Camera module control at the app level performs the basic image settings control: image resolution, image format, white balance, exposure time (shutter speed), aperture, or other settings.
Those are the settings that are defined for the sensor prior to capture the image, and synchronized with the physical settings on the TLR camera prior to the exposure. Once the image capture is performed, the image data file can be shared wirelessly on a network, a smart device (phone, tablet or other similar electronics) or could be saved on the micro-SD card.

Claims (6)

The Embodiments Of The Invention In Which An Exclusive Property Or Privilege Is Claimed Are Defined As Follows:

1. For a film TLR camera, initially designed to capture an image using a photosensitive material, the use of an internal apparatus to change the film plane and projected image size in order to allow the use of affordable camera sensors.

2. Use of electronics assemblies or Digital Twin Lens Reflex System (DTLRS) for film TLR cameras that are comprised of a sensor unit, hardware, and electronics that syncs with film TLRs camera signals and optics to produce digital images at a different location than the original film plane image.

3. Use of modular electronics assembly in conjunction with various sizes of support frames that allow the conversion of various size film cameras into digital cameras.

4. The combination defined in claim 1 & 2, including single minicomputer device or multiple modular devices or assemblies that enhance the system capability (RAM, GPS, Wi-Fi, sensors or filters).

5. The use of the film backpressure plate as a heat sink, dissipating the heat produced by a computer processor or other electronics inside of the film camera.

6. The use of a flash sync signal settings M, X or other, of a film camera, to provide sensor delays for data input to trigger the capture release signal for a DTLRS
or system assembly or devices to capture a digital image placed inside of a film camera body.