[3.1 x 3 x 1.2"] This adapter was optimized for all of the sigma Art line of lenses, and I have not have problems with any of the L lenses I tried.� One of my favorite lenses that does not experience a great amount of aberration is the 135 1.8 and the 50 art.� The others show the distortion around the edges as these lenses were made for full-frame, and not Cropped MF.� �The manufacturer has included an update port, and has already made a couple of improvements through firmware updates, like more compatibility with tamron lenses (at launch it would not recognize tamrons at all), and Improved start up time when turned on and engaging the lens.� The adapter uses the camera's battery so unlike some of the other adapters it doesn't require a power source.� Great build - metal, and feels like the sigma art lens finish.� Lens feels secure on the adapter, and did not bind or get stuck and I have been using this for about 6 months aggressively.� �It has its quirks, I have seen some complain about theirs being too tight or non-functioning on arrival, but BH only provides quality products and adds that level of credibility to an overseas manufacturer/distributor.� Highly recommend.

[3.1 x 3 x 1.2"] Its sturdy and works perfectly, the only downside is that you get to see how poorly most L series Canon lenses perform compared to G lenses. Dont expect fast autofocus. Many testers of Canon primes on GFX did not realize that the default camera setting is to automatically crop with the Techart adapter attached. No, the 85mm 1.2 II and 50mm 1.2 do not cover the full sensor. Youll still get a much better image than the 5DmkIV, but its a shame to not use the much better G glass. The best reason to purchase this adapter is to use TSE Version II lenses, they work flawlessly.

[Leica M] Autofocus works well with most of my Canon L lenses but be aware some lenses will provide vignetting to the point where it might be usable.� I tried some other brands and they didn't work at all and had to be returned. Highly recommend this lens adapter.

[0.18 lb] When I saw this adapter on DPReview TV, I was skeptical that I could finally have Eye AF on my Alpha 1 with my vintage Helios 44M, but after buying this adapter and combining it with a Leica M-M42 adapter, that's exactly what I got! The way you configure it (by setting the aperture) is pretty obtuse, but it does work. Also nice that it includes the docking station to update the firmware through the computer.

If they ever come out with a future version that handles heavier-than-500g lenses, I'd happily upgrade, but for now: I'm very impressed.

[0.18 lb] Plug and play! Tight fit on my Leica SL3 and absolutely no hint of movement

[3.1 x 3 x 1.2"] I purchased this to as an experiment to play around with a few EF mount lenses on my GFX 50S, and its completely changed how Im using the GFX system.  I assumed adapted lenses would be very quirky and not really useable for serious work, but Ive been pleasantly surprised. I now have more EF glass than native glass.  

So far Ive added the Canon 24mm f/3.5 TSE L II, 35mm f/1.4 L II, and 200mm f/2.8 L II, as well as the Sigma 50mm f/1.4 ART and 85mm f/1.4 ART.  All the lenses capable of AF (so all of them but the TSE) are very accurate and focus reasonably quick.  As far as image circle/vignette goes, they all also perform extremely well... the Canon 35 has a tiny bit of vignette that is correctable (aka... soft vignette), and the 24 TS has a bit of vignette when you shift beyond about 8mm (but it also correctable).  

At the end of the day the adapted lenses arent quite as sharp as the native GF lenses (but thats a pretty tall order... the 110 GF is the sharpest lens Ive ever used), but the extremely shallow DOF a f/1.4 FF lens is capable of achieving on the GFX sensor makes it worth it (the 85 f/1.4 for example, gives you the equivalent of something like a ~66mm f/1.1 in FF).  I use the native GF lenses for absolute sharpness, and pull out the adapted EF glass when I want to achieve surreal unbelievably shallow DOF (and some of the EF lenses like the Canon 35 and Sigma Art lenses are still extremely sharp)

[0.18 lb] I saw a lot of videos reviewing this unit before buying it, so I managed my expectations on how it’ll work. Glad to report that it actually work really well with a VM Nokton 35mm f1.2, it focuses well in the center, and even does eye tracking in AF-C on my A7CR. I mainly do travel and portrait so this is a really great adapter. I’m curious on whether it’ll focus as well with a Nokton 50mm f1.

[3.1 x 3 x 1.2"] No problem with a number of my Canon EF, Tamron, and Sigma lens. Even tried my 50+ year old Pentax super takamar 50mm f1.4 lens with Fotodiox PK to EOS adapter. Of course to manage expectations, you have to work in the manual setting on the Hasselblad X1DII and adjust everything but focus is quite clean and you need to deal with vignetting, but that was expected. Well built, solid tight attachment.

[3.1 x 3 x 1.2"] No problem with a number of my Canon EF, Tamron, and Sigma lens. Even tried my 50+ year old Pentax super takamar 50mm f1.4 lens with Fotodiox PK to EOS adapter. Of course to manage expectations, you have to work in the manual setting on the Hasselblad X1DII and adjust everything but focus is quite clean and you need to deal with vignetting, but that was expected. Well built, solid tight attachment.

[0.18 lb] The Fotodiox adapter has much nicer finish and tighter tolerances than the cheap adapters available from China through @, yet it costs far less than the Leica or Voigtlander R to M adapers. There is absolutely no wobble when lenses are mounted, and I trust the latches not to fail. Great quality for a moderate price.