I use my camera to photograph birds from a hide with a 300 mm lens, I use AI servo point focusing; occasionally a bird will take flight but I have a problem getting the single focus point on the flying bird - if I then to changed to the nine points it would be too late. If wondered if the central focus point of the nine has priority over the others and if that was covering a stationary bird that would be taken as the focus point used - if so I could use the nine points all the time and catch a bird in flight as well - I set the camera to 1/1500 sec and burst mode for bird photography.