MetabonesAdapter Canon EF to MFT

Use this for both video and stills on a GH4. It works great on our GH4 - I'm not sure of the firmware, but I don't have an major issue with it.Lens I have used - all EOS mounts obviously:Canon 50mm/1.4Tamron 90mmTokina 11-16mm Pro DXTamron 24-70mm/2.8 Di VC USD (best all around lens we have, works great)Minor issues:- Auto focus is slow, significantly slower than - for instance - when I mount the same lens on a Canon 60D. That being said, I think for people shooting video, or for pros, your gonna get your focus in anyway before making your shots. I use the GH4 focus peaking, I don't have an issue most of the time. However, you must review.- Per above, not for action / sports.Shooting 4k, with the Tamron 24-70, and the light weight GH4. That's a great combo. Most of the time you need no other kit.It's a great tool, for the right use cases.

I love bird photography and have been using my Canon EF 400mm f/5.6L USM with Olympus cameras for some time. When Olympus bodies with in-camera stabilization came along, I knew that they were the answer to adding IS to Canon's fantastically sharp bird lens. I had pretty much given up on an auto-focus solution when I realized that this product was availabe. I ordered immediately before even going to the Metabones website to research. I had been thinking about the new Olympus PRO 300 lens and this relatively inexpensive solution was a no-brainer, must-try.My current camera is the Olympus OM-D E-M5, the older model. The box came in yesterday. I put in on the camera, The fit was tight and secure. I put the lens on. That fit was also perfect. I turned on the camera and my heart sank. Then, I thought to my self, "idiot, take off the lens cap." Then I realized that I had. My heart sank again. I removed the lens. I removed the adapter. I looked through both to make sure there was no obstruction. I mounted it again, same problem. The camera displayed everything but the view of the light coming through the lens. At this point, I thought that maybe the camera had an issue. I removed the lens and adapter and noticed that the viewfinder immediately displayed the blurred, unlensed image. So I mounted the lens again, leaving the camera on and wiggled the adapter a bit while keeping the lens release button pressed, and then it just started working. I wiggled it until the viewfinder image showed up and then just left it alone.I don't know what causes this issue, but it went away and has not cropped up again. Maybe a contact wasn't making an electrical connection? Who knows? I'm not going to subtract a star because of it. Anyway, on to my review of the autofocus performance.So for those of you who have never used the Canon EF 400mm f/5.6L USM, you need to understand how it normally operates when attached to a Canon DSLR to understand my basis for expectations. When the focus limiter is placed in the 8.5 meter position, this lens focuses mind-blowingly fast - eye fast. It is so fast that you can usually just make sure that what you are aiming at is at the pertinent focusing point and push shutter release all the way. The lens will focus before the shutter trips. No sound. Just focus.After earlier seeing reviews of the Metabones Speed Booster's autofocus performance, I wasn't expecting much. Just hoping that the lens would get sharp focus more often than my 50/50 manual focus success rate on birds. I didn't even care if it took longer. But what a pleasant surprise. With this adapter, there can be some hunting, but because the big Canon lens focuses so fast anyway, focus is quick even when it hunts a couple of times. When the image is only slightly out of focus, the performance is little different than with a Canon body.And, best of all, focus is accurate. Again, for those unfamiliar with the Canon 400 5.6L USM, it is pixel sharp on a 16 mega-pixel M43 sensor, a fantastic bird lens. This adapter is not a "Speed Booster" and has nothing in the light path to change the performance of the lens optics. Accurate focus is everything with this lens because DOF can be so shallow. Anyway, I now have an image-stabilized, auto-focus edition of this awesome lens.

There is an issue with the cap covering, every time I try to take it on or off it is difficult and I have to “jimmy” it.

I have to give this product only one star because it simply did not work at all on my Panasonic GH4 (Panasonic firmware v2.4). Whenever I mounted it on the camera and pressed the shutter button, the viewfinder image froze for a few seconds, then went black, with only the aperture number visible in the EVF. After that, I could not even turn off the camera, and was forced to remove and reinsert the camera battery. This was repeated many times, with two different lenses, with exactly the same results each time. I tried updating the Metabones firmware to v2.0, but that made no difference.The two lenses I used were the Canon EF 70-300mm f/4-5.6L IS and EF 24-70mm f/2.8L II. Identical results.Since another reviewer stated it worked on his GH4, I suspect I may have had a defective unit, but since it was an Amazon Marketplace item, I can only return it, not exchange it. If I decide to order another one in the future, I will amend this review if the results are different.

Fast focus on my 70-200f2.8 and my 18-55f2.8. Also work with hi-res captures. Highly recommend. It’s attached to my OMD EM1 MK2 Olympus m43.

Perfect. and with firmware update even better. I can use now all Canon lenses I have on my Olympus, with no issues at all

As others have noted, I, too was sold a Speedbooster that turned out to be used. I was pretty excited to get it and should have been more alert to the fact that it was in a scuffed plastic box, there was no Metabones packaging or paperwork, and the UPC on the plastic box had been covered in magic marker.It took me a while as well to figure out that not only was it used, it was broken. The Speedbooster worked only sporadically, making it hard to understand if the issue was me, my camera, my lenses, or the Speedbooster.My Speedbooster is now on it's way back to Metabones for repair, which I'll need to pay for. I contacted this vendor who essentially said, "too bad for you".Avoid this vendor.

Great product! Works exactly as it should, which is what you expect when buying Metabones.