More specifically to the Canon 7D -
In Full Auto everything is done for you even "Sports Mode"- page 52
Creative Mode is the same, but you can change a few things - page 53
In P, Tv, Av, M, or B you control a lot more... - page 57
The Drive Modes are: - page 83
- One Shot AF for Still Subjects
- AI Servo AF for Moving Subjects
- AI Focus AF for Automatic Switching Between The Two
Now the question is one of selecting the proper AF Area
- Default AF Area Selection Modes - page 87
-- Single Point (Manual selection)
-- Zone AF (Manual selection of a zone)
-- Auto Select 19-point AF
- AF Area Selection Modes Added With Custom Functions
-- Spot AF (Manual Selection)
-- AF Point Expansion (Manual Selection)
Each one is explained from there
There are also some good write-ups and videos at
http://goo.gl/jsl94More specifically to the Canon 7D - br In Full Aut... (