bought a 5€ adapter once to test the lenses. It worked fine. This works fine too, but the build quality makes it look like it's part of the camera itself. Very sturdy and good feeling. In love with it. IMPORTANT: If you are exact picky and are taking pictures of very far away objects (eg moon) and need absolute precision, this adapter (the same as any adapter on the market) doesn't focus _exactly_ until infinity. It seems to be designed with about 0.5mm more flange, and at maximum aperture (maybe for astrophotography) it falls back just a bit. Maybe removing the ring mount and sanding it a little (is 1mm thick) could help get a perfect infinity focus. Another option is to stay at f8~f11 and then tend to get decent focus at infinity (tested on focus centers 50~200mm). Quick test, focus seems to be off by 0.5mm max (I removed the 1mm ring, tested on hand and it focuses past infinity). This also seems to match the flange difference needed: Canon FD = 42mm; Sony E = 18mm; flange difference = 24mm; adapter thickness (from E base, not bayonet, to Canon FD bayonet) = seems a lot like 24.5mm. So you know. Great adapter, just grind the ring mount down a bit.