In this article I will be covering the Sony A7II and the Metabones IV T Smart electronic lens adapter, to try out how well the on sensor phase detection auto focus works with my Canon EF Lenses. I used the lab scene lit with only one light to keep things fairly dark for testing.
I used the latest firmware for the Metabones IV lens adapter (currently at V0.47), and you can get that Here >>
The Sony A7II firmware is at V2.00 and can be found Here >> I also wrote an article with a video tutorial on how to update your camera firmware if you need Here >>
For this testing however, I used the Center AF area and Auto ISO on the Sony A7II. I shot wide open with all the lenses to see how well they worked at the fastest aperture.
The Canon EF lenses tested were my 70-200mm f/2.8 L IS, 135mm f/2 L, and 24-105mm f/4 IS. I love these lenses and have been holding off on selling them for so many years. Take a look at this video below and see exactly how they performed from the back of the camera perspective.
Metabones T Smart Adapter Mark IV Focus Testing, Sony A7II, Canon EF L Lenses
Well, as you can see the lenses performed pretty good in the lab tests wide open overall. However, when I got to the slower 24-105mm f/4 lens, focus speed did drop noticeable. This illustrates how the faster aperture equals faster auto focus when using the on sensor phase detection. The EF 135mm f/2 L Lens was the fastest at acquiring a focus lock, fallowed by the EF 70-200mm f/2.8 L IS Lens. The EF 24-105mm f/4 IS Lens was the slowest of the bunch and that is because of the max aperture speed.
I thought I confirmed this by putting the 135mm f/2 lens back on and stopping it down from f/2 to f/4. However, I was in a lower light environment upstairs when I did this. It did seam like the 135mm f/2 lens slowed down, but this was only due to the lower light, and not because I changed the aperture to f/4. The lens stays wide open when autofocusing with the Metabones IV and does not give a “live preview” like I was thinking at the time. It only stops down when the actual shot is taken, just like how a DSLR works. Therefore, the faster the max aperture is, the faster the AF will acquire a lock it seams like based on the testing…
Thanks to Mike for the correction in the comments below, as I was wrong about the stopping the lens down and it effecting the AF speed on the 135mm lens. It has not effect when you stop it down, because it remains wide open.
Bottom line here is the Metabones IV worked very well with the Sony A7II and my Canon EF lenses. I was impressed overall and the performance is leaps and bounds better than my Metabones III in the same situations. The best alternative to the Metabones IV looks like it might be the new Sigma MC-11 electronic lens adapter that was just announced. I will get that unit asap for comparative testing 😉
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