VILTROXEF-M1 Electronic Aperture Auto-Focus AF Lens Mount Adapter Automatic Converter Compatible with Canon EOS EF Lens to Panasonic GH5S 4 3 2 1 GF G100 Olympus OM-D E-M1 M5II M10II/E-PL8 7 5 3 2 1

This adapter does not seem to work with my Canon 135mm f/2.8 prime glass, even though it is listed as compatible. It does work with my Sigma 120-300 f/2.8 zoom lens.The autofocus does get sharp, but it seems to do a lot of seeking, or sounds like it is stepping up to the final focal point.I would not use it for sports, but for landscapes, plants, people and wildlife, it will do the job for you.But I do wonder whether I need the M2 version to work with my 135mm lens.I tried it on both my Olympus PEN E-PL2 and my OM-D EM-10 cameras, and the 135mm does not work. I get a black screen. The Sigma works on both camera.I did not rate the IS, as that is a function done by the camera.I primarily purchased it for my Sigma anyway, and I still need to continue to test it out. As I get used to it, it may work for sports, with a manual focus assist.Sometime this year I will upgrade to the latest EM10 body, and may even get better results. I still would recommend this for anyone who wants their Canon EOS lenses to work on your Olympus micro 4/3rds bodies.

I tried this on a Lumix G7, with a Cannon EF 75-300mm zoom lens. When you turn auto focus on, the lens goes crazy trying to focus on something, but never actually does. It just twitches infinitely back and forth trying to make up it's mind on what to focus on I guess? The Cannon lens works fine on the Cannon Eos camera it came off. When you actually press the shutter release it stops dancing around and does focus on "something" but you never really know what. Now, if you turn off the auto focus both on the lens, and the camera it works great with manual focus. Fit and finish is great - locks onto the both the lens and the camera body as good as you could hope for. Maybe other auto focus lenses work better with it than the Cannon EF ones?

Works great with some lenses, fits ok on GH4 body

Works fine with a Rokinon Special performance 85mm f/1.2 and a Tokina Opera 16-28mm f/2.8, but doesn't work at all with the Canon 200mm f/2.8L USM, which is literally on the list of supported lenses. I suppose it could be an issue with the body since I'm using an E-M1 Mark III, but there is no way to update the firmware on this adapter so there's no potential for improvement, really disappointing considering the 200mm is the only reason I bought the adapter in the first place.

This serves its purpose. The autofocus works. Not perfectly but gets the job done. It’s so worth the price for sure

I use the Viltrox EF-M1 (firmware 3.2) with a Panasonic G85 (firmware 1.3). The Canon lenses I have tried are EF 50mm F/1.8 STM, EF 35-105mm F/4.5-6.5, & EF-S 18-55mm IS II. These are pretty much the standard lenses for Canon and they are listed as supported lenses for this adapter.Here are the cons:1) Focus is slow and unreliable. It constantly searches and when it does archive focus, the picture is slightly out of focus (or blurry) about 50% of the time. I used the EF 50mm F/1.8 prime lens and I cannot produce any usable photos while taking pictures of my child who moves a round a lot. The focus is way to slow and unreliable. This is not a problem when I use the lens with a Canon T6 or 1D.2) The adapter would reset itself in autofocus mode after every shot. While it resetting itself, it locks out the G85 (or the camera is unresponsive) for 3 to 4 seconds. While it is "reseting" itself you can see on the G85's screen that the aperture is set to 0.0 for the duration and then is set back to the value when you took the photo. The screen also displays all the zebra highlights of the manual focus aide. All this takes about 3 to 4 seconds. When you put the lens in manual focus, there is no lock up (or reseting); you can take photos as fast as you can click the G85.3) For some reason the adapter would not allow the G85 to record a photo you have taken. I set the G85 to hold the review indefinitely after every shot yet, the adapter somehow disable this feature. So there is no review and sometimes the picture is never recorded to your memory card even though the G85 released the shutter.I would not recommend this adapter. It has too many bugs and hiccups as it is now, March 2019, firmware 3.2. Maybe Viltrox will fix this in the future. The price is right only when it works. Making things work is difficult but if you are going to sell it for $136, it should work. I applaud Viltrox for trying to make stuff but a big boo to Viltrox for not testing its products before selling them. The Panasonic G85 and Canon EF 50mm prime lenses are as basic as the MFT world is going to get. So test it well before you start selling stuff.

You have to twist on and off a few times for booster to reconize lens electronics. Also sometimes give wrong aperature numbers. With rhat being said. Still a better option than $600 metabones unless you truly rely on autofocus.

I'm using this with a Canon EF-S 55-250 f/4-5.6 STM lens mounted on a Panasonic Lumix G9. Autofocus is slower than a native m4/3 lens, but quite usable - even in low light. It does sometimes miss attaining perfect focus at long distances, in which case a second attempt does the trick. At close distance the AF nails it just about every time. Continuous AF does not work at all, as expected. Using firmware 4.0.Overall, the Viltrox is functioning as well as I could reasonably expect, and I wouldn't hesitate to recommend it. There are several other EF lenses I intend to pair with this.PS - Another reviewer stated that there is no way to update the firmware, but that is not true. There is a USB port on the side of the adapter. Plug that into your computer, go to the download center at Rollei (European site for Viltrox) and read the instructions. It is an easy drag & drop operation.