gopro once released a stereo system with synchronization cable for the gopro hero3+ black edition (2013). it controls both cameras from one camera and synchronizes all settings, including exposure and white balance, and the recording of frames. the resulting files are also automatically named with a corresponding 3D_L or 3D_R prefix. the file numbering that follows after the prefix is not synchronized, though. additionally, timecodes are added to video file metadata.
the supported recording formats per camera, that i am most interested in, are 2160p15, 1080p60, and 720p120 for videos, and 4000x3000 for photos. this allows for a combined resolution of 3840x1080 for videos, or even 7680x2160 with 15 frames per second, and 8000x3000 for photos. also notable is the protune option, which allows the customization of more recording settings like color profiles, iso, and shutter speed. the super and 17:9 formats are wide formats.
the cameras each have a dimension of 58.4×38.1x20.3mm. the interaxial distance is variable from a minimum of about 29mm to about 90mm, limited only by the length of the sync cable.
gopro did not continue stereoscopy support with later models.
the minimum required parts are:
gopro hero3+ black edition
the cameras should be updated to the latest firmware. i bought the cameras used and faced some issues:
depending on the desired positioning of the cameras, the dual hero sync cable might have to be modified.
to have the cameras attach directly next to each other, the cable has to be modified to come out of the box at the bottom instead of the side. to achieve this, i opened the orange (L) dual hero sync box with a small torx-like screwdriver, cut off the corner rubber with an exacto knife to make it fit better, and re-positioned the cable before i closed the box again. for the time being, i used a putty-like adhesive to fix it and reduce stress on the fragile internal cable connections.
the software once provided by gopro for post-processing might not be available anymore. regardless, it would probably not work on my linux system. therefore, i wrote a shell script that uses a few common tools to create combined side-by-side versions of photos and videos. one image-side is rotated, because the dual hero system has one camera upside down in its standard configuration and automatically rotates the image on creation.
in the current version of my setup, i used these additional parts:
(not yet received) replacement lenses with a focal length of 8.25mm, which corresponds to a 47mm focal distance on a 35mm sensor, the closest to 50mm i could find
it has yet to be seen if the lenses will have an ir cut filter
the default lenses add fisheye distortion
the status of my current build is as follows:
so far, it works nicely as a handheld. it has yet to be seen if rubber bands will be a good solution for attaching the cameras to a mounting plate.