That’s interesting, must be very rare or a prototype. One thing I noticed is there are two infrared focusing eyes, one for each lens. I would think you would want one so the focus of each lens is the same. If each lens was focused different it could screw up the stereo image.
If it's a prototype (as seems likely) they probably just didn't fill in or close over the second focus eye. More likely (from the mount spacing and such) it's a homebuilt or a novelty item that doesn't actually work in any way. It'd need the auto advance reprogrammed to handle the skip-frame (shoot, wind one, shoot, wind three), if in fact the mounts are actually two frames apart. Seems unlikely to actually produce useful stereo images...
There were firms who made combos of SLRs in small series.
The colours of the mount indicators likely hint at which lens goes to which side, as possible inter-lens coupling-mechanics typically would not show such at first sight.
Why bother taking these out if it works with them? Furthermore to save on complicated electronic coupling both cameras might still meter on their own. With integral metering that should work. And then you need those parts.
Photrio.com contains affiliate links to products. We may receive a commission for purchases made through these links. To read our full affiliate disclosure statement please click Here.