AI Servo - Number of Focus Points

[Waddizzle]

I am basically a still photographer.  Apparently, my renewed interest in photography has created a reputation of me being some sort of photography guru.  HA-HA    So, folks with smartphone cameras have begun asking me to come and take pictures for them of this, that, or some other event.  No weddings, just Little League games, and the like.

Shooting stills means using One-Shot focusing mode, which may not  be best for moving subjects.  So, I've been exploring and experimenting with AI Servo mode.  Which, brings me to a question that I cannot answer. 

Does it matter if I am using just the center focus point, or should I need to turn of manual point selection altogether? 

So far, my experiments have been inconclusive.  My shots are in focus, but I am attributing that to pre-focusing.  I get much better results by pre-focusing, than when I don't.  Keeper rate is pretty much the same with manaul AF point selection, no matter if I use One-Shot or AI Servo modes. 

I pre-focus on a player, or where I expect a player will be: i.e.; focusing on the base ahead of the base runner.  I can get good shots, like the above play at third base.  [the shot has been cropped to remove faces and team information]

But, forget about refocusing on an outfielder chasing down a ball.  The kid is running, so One Shot doesn't work out very well, but neither has AI Servo with only the center point, manually selected.  Turing on all of the AF points, 9 in a 6D, results in the camera frequently focusing where it wants, not where I want it to.

I guess I am saying that it seems that I have not been able to have the camera actuallly track a moving subject.  So, do I need to turn on all AF points, in order to make it track in AI Servo, or not?  For me, I am having bad luck relying on automatic AF point selection to pick out the running kid in the outfield, instead of a background tree, or something.

[jrhoffman75 · Accepted solution]

This is an excerpt from a 1D Mark IV guide by canon, but the concept is the same for all cameras. AI Servo is doing math, and you need to give it a little time to compute.

[ebiggs1 · Accepted solution]

"I hope a 6D mark II ..."

"BTW, I am 6'8" and 220 lbs."

If anybody I have ever met should get a 1 series it is you.  Your size is a match.  I can't imagine you are comfortable with a Rebel.  Or even a xD series for that matter.  My size and the total lack of being impressed by a 6D was just another plus sign for a 1 series.  If you can't drop the coin on a 1Dx look for a clean 1D Mk IV.  Once you go 1 series, you will never go back. That's a fact, Jack!  IMHO, of course, as always.

[Waddizzle]

Thanks, John, for the brainstorms.  I have never paid attention to the tracking adjustments before.