I hate reading manuals...but i did find some good info on YouTube.
I would go there first. I would try to stick with Primes but you have a nice
24-70 and decent 50. Adjusting from the AF and system on the T2i to 5D takes getting used to but i don't
have a prob with it. Just takes a little time and practice. Even the heavier weight of the body.
Thanks! Starting to realize what other photographers were saying on this site regarding the poor AF function in low light now....
just stick with the center point only and only use f2.8 or faster lenses, and don't use AI servo...
The centre point is OK with f/4 lens, although f/2.8 lens are better
in decent light f4 is ok but i find the 24-105 really struggles in poor or very low light but the f2.8 lenses and fast primes can get focus lock ok.
The AF needs good contrast to focus in low light - no good pointing it at a plain dark wall. The centre point is more sensitive at F4 and even more at F2.8 - the 5DII is the best of all at focussing in low light. Also see this posting by neuro