Hi, this adapter is for Canon EOS mount lens to Sony E NEX mount camera, we checked the sony a 7iii camera mount is E mount , this adapter can fit it , but you can reconfirme it , thanks.  

The adapter for a EOS body to a Canon FD manual is the adapter needed. The Canon AE1 uses the FD/FL lens mount. The one I purchased works without a hitch. Mine is a K&F Concept Pro lens mount for Canon FD, FL lenses. From a F1 to a 5D Mark 4 with no issue. 

Yes 

I have the Nikon F mount version and it works with the GH5. It's all manual focus, of course. There is no lens data transmitted to the camera. 

The adapter will mount the lens and you will be able to use it manually. However, my copy of the adapter does not allow the lens to be fully mounted all the way until it clicks into place. It doesn't quite make it, but it's still very solidly mounted. Also, the manual aperture linkage doesn't work properly (on my copy, at least) so exposure is controlled only by shutter speed and/or ISO. You will be able to manually focus and zoom the lens but no VR, of course. It will be a frustrating experience. Instead, get a 14-140 Panasonic zoom if you can afford it!