In the recent months, I was playing around with stereoscopic photography. That is taking two pictures side by side to generate an 3D vision. There are several ways to take two slightly shifted photos of a subject:
- Shifting the camera between two time-delayed exposures
- Using specialized 3D lenses, which project two shifted images on the camera sensor
- Using two cameras mounted side by side
Shifting the camera between two time-delayed exposures is the easiest way to start with stereoscopic photography. Take a photo, shift the camera by approx 6,5 cm, and take a second shot of the same scene. In the post-processing, both images can be combined into a red-cyan-image, which can be watched using red-cyan-glasses, or to an MPO file, which can be watched on a 3D capable device (e.g., a 3D TV or smartphone using google cardboard). A pretty easy to use software for stereoscopic photography is Stereo Photo Maker.
However, a problem with this method is that one can only take shots of still subjects due to the time delay between the two exposures. People usually cannot hold their position for even that short delay and already moderate winds can move leafs and grass. Both causing the images not matching to each other and therefore to ruin the 3D effect.
Specialized 3D lenses or cameras are rare and sometimes expensive. Personally, I only tested the Panasonic Lumix G 12,5 mm F/12 (H-FT012) for Micro Four Third cameras. The lens works ok for small subjects but the stereo base, i.e., distance between both lenses, is too close for subjects at distance. As two images are projected on the same sensor, the number of pixels for the picture are in the best case just half the sensor pixels. So, image quality isn’t the best.
There are other solutions like, e.g., the Kula or Loreo products. I never tried them by myself but I expect them to have the same issue with the sensor splitting.
Finally, the best solution is taking two images side-by-side at the same time with separate sensors.
A few specialized cameras, e.g., the Fujifilm FINEPIX REAL 3DW3, provide this out of the box. However, those cameras are no longer in production and can only be bought second hand. As they are rare, even second hand prices are very high. Another issue is, that those cameras do not provide interfaces for an external flash.
An alternative is mounting two DSLR or mirrorless cameras side by side and to trigger the shutter release simultaneously. This can be archived using expensive of-the-self gear or by a simple do-it-yourself solution.
I build a Quad Remote Shutter Release Adapter for Canon EOS 550D (or similar) by myself. Those Canon cameras have a 2,5 mm stereo jack for a remote shutter release. So, the goal was using one remote shutter release to trigger multiple cameras.
Note: several Canon cameras, e.g., EOS 7D Mark II, are equipped with a proprietary socket instead of a 2,5 mm stereo socket.
A remote shutter release for Canon consists of two switches. The first for the auto focus and the second for the shutter release. Both switches are operated by the same push button. A half press closes just the auto focus switch and a full press both switches. If the switch is open, a pull-up resistor applies Vcc to the input of the cameras integrated circuit. A closed switch will connect the input with ground.
Such switches are very specific and not widely available at electronic stores. Therefore, I decided to build a Quad Trigger Release Adapter Box which connects an off-the-shelf remote shutter release with up to four cameras.
The box consists of four 3,5 mm stereo sockets to connect the cameras and a 2,5 mm stereo socket for connecting the off-shelf-shutter release. The cameras are connected with adapter cables with a 3,5 mm stereo jack on one and a 2,5 mm stereo jack on the other side. 1N 4148 diodes are used to decouple the inputs of the cameras.
I didn’t used 2,5 mm stereo jacks on both sides as such cables are not common and hard to find. So this design decision was made just because of the better availability of cables with 3,5 mm stereo jacks.
The next step will be experimenting with different camera mounting options, different focal lengths and stereo bases.
As I currently do not own a second 550D. So, the first tests will be done in cooperation with other photographers.
Disclaimer: I am not accountable for any damage caused by building and using your own Remote Shutter Release Adapter. Connecting your camera with DIY hardware is at your own risk and responsibility.