The AI Servo tracking sensitivity is set with the C.Fn III-1 setting. I wrote about it in: C.Fn III -1 AI Servo Tracking Sensitivity. Its purpose is to direct the Canon 7D on how fast it should switch focus, when something come in front of your subject.
My own setting used to be to setting to:
Slower than medium, but faster than slow
This is a good setting, if you are trying to track an already moving object/person/animal and something/somebody interfere in front. But what about an object/person/animal that is not moving, and then decides to move?
That’s where I have found that this setting didn’t work well for me. I have found that I’ve missed too many photos as out of focus, when the focus is still at the point that the object/person/animal was, and not where he is now.
I’ve found by mistake that changing the tracking sensitivity to
Fast. It transformed my Canon 7D into a nervous, very nervous and trigger happy camera. Much too fast for me, but I’m an “old fart”, my reflexes must become too slow.
- So as an overall setting, I put it back to the middle, neither fast, neither slow.
- Guess what? This was Canon original default setting for the 7D! I guess they must have spent time to do studies to see what works best and use it as default.