Re: RF 100-500 - trouble with autofocus and birds
R2D2 wrote:
Jeffrey_L wrote:
Here are a couple of images that came out blurry.
Many thanks for posting these! Lots going on. Usually when there's a major failing there's more than one factor involved. That's the case here.

The goose does appear to be back-focused a bit (as mentioned it's common over water). But the bigger issue is the too-slow shutter speed (lots of motion blur evident), exacerbated by you not tracking the subject perfectly. Part of this could also be caused by the image stabilization (if you had it turned on). Less motion blur means better AF results!

I'd suggest trying the settings I posted earlier (to use as a baseline). When you're out shooting, it helps to preset the focus to about the distance that you expect the birds to appear. If nothing else, infinity focus works better than closest focus (and be sure to use the lens' focus limiter). In difficult circumstances it helps to wait a tiny bit (until you are tracking well) before initiating AF.
I like using the "Auto" Initial Servo AF setting for BIFs. It can do much better than I can for initial AF acquisition. I only use the other setting when I have to pick the subject out of a group.

AF picked up on the much more contrasty bushes in the background. If Face/Eye detect did not lock focus properly right away, then use the Spot AF and aim at the bird's legs. Servo AF loves contrasty vertical objects. With this shot I might have even used the Spot AF first off, since the Eye/Face AF boxes can indicate eye/face lock, but the camera still locks onto the nice contrasty back branches (this does happen).
Honestly, the biggest problem was when autofocus would hunt and not allow me to get a shot off at all.
I shoot with exactly the same combo. I find that I get a much better hit rate when I turn OFF Exposure Simulation. The camera's AF uses this (brighter) image/data for focusing.
Be sure to report back when you get another chance to get out. Best of luck!
R2
That last shot would be simplicity itself to a bog standard DSLR surely with single spot focus? Is it getting over complicated? Can you disable most of the fancy AI stuff?
https://www.flickr.com/photos/dcweather/