>The AF system has a function called Predictive Focus Tracking >in AF-C mode. What this means is the camera will anticipate >the movement of a subject and adjust accordingly - not just >when 3D mode is selected.
How does that interact with the A3 (Focus tracking with lock on) and how that affects ones need to release and re-touch the AF-On or shutter?
Consider basketball, if I'm tracking the ball from player to player (i.e. moving the camera between two players), And A3=0 and 9 point, I usually just pan to the other player and do not remove my thumb from AF-ON, and assume that it will refocus on the new player immediately.
With A3=5 (for example) I would assume there may be a lag as it delays shifting focus, and it would be better to remove and re-press the button. But with A3=0 (off) is that still true?
Put more succinctly, if you need to shift to another subject nearby very rapidly (not while shooting but preparing to), are you better off just shifting to it, or releasing focus, shifting, and re-pressing the button?
I should add that usually but not always VR is off when I'm doing this, but the habit comes more from when VR is on and I don't want it to be starting and stopping and not be "ready" when I shoot.