About a year ago I was awarded a generous amount of money from the Arkwright scholarship fund with which I decided to take a good old film camera and ‘digitise it’ using components taken out of the smallest digital camera I could find with a reasonably sized sensor, the Sony NEX-5. The analog camera I chose was the Konica Auto S3 rangefinder because it has a stellar fixed 38mm f1.8 lens with an unobtrusive internal leaf shutter. The viewfinder is very clear and being a rangefinder is easily adjustable for use with a different focal plane. A rangefinder mechanism allows the camera to be small (no large mirror) and won’t get in the way of the sensor which has a protruding AA filter on the front. Unfortunately the camera doesn’t have a built in diopter to adjust for glasses wearers but I managed to cut an old glasses lens of mine to fit into the viewfinder as a diopter adjustment.
To start I dismantled a NEX-5 camera and set about trying to determine what components were necessary for the camera to function. Many of the expected components were required, the circuit board, sensor, SD card slot, battery connector. Unfortunately the camera also requires the motor module for the shutter to be attached or it shows a ‘camera error’ screen. This meant I needed to include the motor and three adjoining cogs in my already crowded design.
Next I needed to decide how to house the digital components and attach them to the film camera. My school had recently acquired a 3-D printer so I started designing a CAD file which would house these components using Solidworks and a pair of vernier calipers. I decided to replace the original back of the camera with a completely 3-D printed part, which is shaped to mate with the camera perfectly and to be hinged at one end with a clasp at the other to work with the original locking mechanism. I designed it in two parts, the bottom part holding the SD card slot, the sensor, the motor, cogs and battery. The top part holds the screen and buttons, and the main circuit-board is held between the two parts. In my final design there were also small covers for the cog assembly and to support the buttons.
I also designed a replacement an ON/OFF mechanism in my final design which requires the film rewind wheel to be pushed down for the camera to turn on. This also held the design firmly in place. I also designed a replacement trigger which could house a miniature electronic switch which would be pressed as the trigger was being pressed down and released afterwards. This activates the digital sensor for the duration of the trigger being pressed (the digital camera being on the BULB setting), during which the film camera shutter is activated causing the sensor to be exposed as film would be.
Most of the components could be placed roughly in their original positions and so could be connected via the original ribbon connectors but I moved the battery and the buttons to the left so the connections needed to be extended by wires. This proved difficult when soldering the wires for the buttons as there are 8 wires in a very small space and soldering onto a thin easily melted printed circuit.
I first tried printing my design at school but the quality wasn’t high enough for such detailed work, so I sent my design to a 3-D printing company in London which used the incredible SLS printing method to create a strong, accurate and flexible print in nylon.
I was impressed with the quality of the first print and it was close to a final design but had some problems that couldn’t be fixed without a reprint so I redesigned it and printed it again. The result was perfect so I applied some cosmetic changes, cutting some spare leatherette to fit and painting it black. Finally I connected it to the adapted Konica, from which I removed some material to make space.
After I had finished all of the assembling, I calibrated the lens to focus to infinity using the camera’s live view, and then calibrated the viewfinder to focus accurately.
These videos show the operation of the camera.