I\'ve been using Canon DSLR cameras since they came out with the original Rebel (300D) years ago. Typically I\'ve gone with defaults in the menu options since I figured the defaults are what Canon feels will work best. That has been the case for all Canon L lens that I\'ve used.
However, I began to wonder if there was something in the menu options that might be tweaked to gain AF when shooting BIF shots with non-Canon L lens. I think I found something, something I was surprised to learn.
Personally I\'ve always used center point AF when tracking BIF shots with usually good results and had mixed results when using automatic AF points.
As it turns out there is a menu feature that is turn off called \"AF Point Expansion\" in both my Canon 7D and Canon 5D mkII. It only works if AI SERVO is turned on, which of course is necessary for tracking BIF shots.
