AGeoJO
Offline
• • • • • • •
Upload & Sell: On
|
scott f wrote:
I mentioned in a previous post that I would be doing a tough test of the AF on my MBIV. The equipment used was the Canon 400mmf4 DO II, MBIV(latest firmware) and A7RIII. I spent a few hours attempting to photograph Longtailed Ducks in flight and perching birds.
So, onto my observations. Continuous AF is hopeless with the fast flying ducks. The acquisition is far too slow, and it simply cannot reacquire focus once it loses the subject.
I decided to try pre-focusing and I had limited success. It seems that the initial acquisition is the best it can do, after that it simply cannot change focus quick enough to follow a bird flying towards you.
The few shots I did get were either from birds flying parallel to me or the first shot or two in a sequence. Nothing flying towards me was in focus. The AF isn't even close to being capable.
I did try slow flyers such as gulls against a clear sky, and it seemed to be able to handle that situation.
Next stop was perching birds like woodpeckers, cardinals, and sparrows. Once again the focus is slow, however, once locked on, the focus accuracy was dead on with nearly every image sharp. However, it's dog slow to focus if it starts substantially out of focus or in some cases, it didn't even try. In fact, it often took long enough that the birds were gone by the time it got around to the correct distance.
I found it helpful when the focus was way off to manually focus the lens to get it close, then allowing AF to take over.
I decided to try the continuous focus on cars moving around 60km/h. Once again the initial focus seemed ok, but it couldn't track the cars driving towards me. So again, the first shot or two would be acceptable, but all others were soft.
So in summary, with that particular combo, the focus works but is very slow, and continuous focus worked only on very gradual distance changes. Hopefully, Metabones will come out with another firmware update to improve things.
...Show more →
You didn't specify the mode used on the Metabones. If you used the green mode, then that's a blow to the AF performance of the A7r III. Here is the area where the A9 shines. If you used the advance mode, then I am afraid that you may need to re-do the test with the Metabones in the green mode.
|
