MMA photography and autofocus

[Reebert]

Hello,
My D800 and 85 1.4 were having a tough time photographing an MMA fight. The autofocus would keep on locking on the chicken wire of the cage. I'd have to manually over ride the AF. I noticed I got better results when I stopped down a bit.
Any advice?

thanks!

 

[Russ_]

From a non-educated pov I would have thought it would be worse stopped down, as the wire would be more in focus. Interested to hear what others say.

 

[Aqualung]

Give us some more background on your focus settings...

 

[ImageReflex]

You've hit upon one of the fundamental weaknesses in all AF systems--they lack the ability to understand that the contrast pattern created by wire or netting is not supposed to be the point of focus. As far as I know, there are only three ways to deal with the situation: (1) switch to manual focus (since your brain won't be fooled as easily as the AF system); (2) get sufficiently close to the wire or netting so that it is well out of the possible focus range, and if possible, right up against it (this may impact the light coming through the wire/netting, but the AF system should be able to focus on the inside of the cage); or (3) shoot with a longer lens so that you are effectively following the advice in #2 without being right up against the wire/netting.

Turning off the AF is likely to be the best solution (assuming, of course, that you can adequately focus the 85/1.4 manually).

Stopping down really won't help; if the AF focuses on the fence, gaining some depth isn't going to change the fact that the point of sharpest focus is the fence.

 

[ReLLiK75]

When I shoot MMA, I photograph right up against the wire with the lens hood attached. I shoot wide open and the wire almost completely disappears (depending on the shot). I have my camera set to AF-C and D21. You'll need to crank your ISO to at least 3200 so that you can keep your shutter speed high enough to stop the action.