I think it's already been said a million times that the center point focus works fine on the 5D. Try using an outer point for action, see where that gets you.
Dancing is hardly action ;-) It's recreation, kind of moving statues I have shot actions like these with a classic view camera and had the time to manual focus on the stage :P. The positions are very well predictable. Anyway, not to say this is no EOSfun Thanks for sharing and trying to tell us that the 5D and 85L with bad reputations for fast accurate autofocus are very well capable of shooting great shots in the near darkness of a theater even if the subject moves. It should inspire more people to use their 5D with fast lenses in available light situations where a smart use of gear and the photographers brains and creativity are more important than terrible apparatus
jcolwell wrote:
Why on earth would you do that? I use centre point focus for all subjects with the 5D, even for statues.
Agreed. Wide open? at F 1.2? What would be the point of that, almost nothiing would be in focus.
Shot number one is coming right at me. I would say the keeper rate ran at about 80% but as noted not a lot of the shots were coming right at me. AIServo single shot btw.
I tried using the outer AF point but it was near impossible to keep it on the target. Hence I stopped it down a bit and went to the center.
I wouldn't call 85L "terrible for action", but it's not the most suitable lens for it, and I lump it in the same poor AF responsiveness group with 50 F/1.0, 180L and 800L.
Granted, if the light level is very low, then superfast lenses like 85L and 50 f/1.0 are the only ones that still allow auto focusing albeit slowly.
When photographing action, the key strategy with those slow (or screwy) AF drive lenses is in prefocusing to the distance of the anticipated first contact with the target.
These two shots were done a few weeks ago with 1DsMkII + 85L, at f/1.4 and f/1.8.
I am not sure why is that I haven't shot those with the lens wide open, however, at those distances to target that wouldn't have made any difference.
I did some ballet a couple of months ago with the 85 1.2 wide open on a MKIV. I will say the MKIV made the 85 behave pretty well for low light action at f1.2. It was kind of fun using it wide open and experimenting with techniques.
This shot below shows a dancer on a full run at a 45 dgree angle towards the camera. 85mm is really a great FL for these kinds of shots assuming you have access to shoot close to the stage. The 50 1.2 would do well here too, but at a different perspective. Overall I was very impressed and confident that the MKIV/85 1.2 combination would provide a good enough keeper ratio to shoot these as a paid gig.
I didn't try the 5dmkII with the 85 in this session.
jcolwell wrote:
Why on earth would you do that? I use centre point focus for all subjects with the 5D, even for statues.
What if you don't want your subject in the middle of the frame? I was shooting hockey the other day and I would have loved to be able to place the player more on the right side of the frame but with a 5d2 it's a no-no if the subject is moving
Bullseye5d2 wrote:
What if you don't want your subject in the middle of the frame? I was shooting hockey the other day and I would have loved to be able to place the player more on the right side of the frame but with a 5d2 it's a no-no if the subject is moving
You should be ok to crop away with all those MPs at your disposal.
As long as you have an idea of where the action is going, great work can come from an 85L; dance recitals, knowing a gymnastic routine and lateral moving subjects are all relatively easy to perform.
Thanks for sharing 
and trying to tell us that the 5D and 85L with bad reputations for fast accurate autofocus are very well capable of shooting great shots in the near darkness of a theater even if the subject moves. It should inspire more people to use their 5D with fast lenses in available light situations where a smart use of gear and the photographers brains and creativity are more important than terrible apparatus