Stereo microscopes are branched out from other light microscopes for the application of viewing “3D” objects. These include substantial specimens, such as insects, feathers, leaves, rocks, sand grains, gems, coins, and stamps, etc. Functionally, a stereo microscope is like a powerful magnifying glass. Unlike a compound microscope that offers a flat image, stereo microscopes give the viewer a 3-dimensional image that you can see the texture of a larger specimen. 

I use it on the Sony Alpha 6000 with a manual FD 50mm. AF and aperture transmission are not an issue here. Actually, the adapter only keeps the lens at the right distance in front of the sensor. This works great and I think it will be the same with the Alpha 7III. 

It’s a little tight on my a7III. I bought the Fotodiox brand for my Nikon glass and prefer the fit a bit more. Still works however, just ended up buying a Fotodiox for my Minoltas as well. 

yes, i had no problems with infinity focus with this adapter. the only FD mount lens i use anymore with my sony is a vivitar 20mm, and i pretty much only shoot infinity focus with it. 

Yes. I bought this to mount my Canon 50mm FD to my Sony a6000. It works awesome!