7D Servo AF starting point

When using Servo AF on earlier cameras, like the 40D, you have two options for selecting the AF point.

1. Select it manually, in which case the camera starts and continues to track with that single point.
   
2. Select automatically, in which case you have to start tracking with the center point, but then (if you are lucky) the camera can hand over tracking to any of the other eight points, in case your center point looses track of the target.

1. Spot AF, where you manually select a small AF point for initial focus, as well as for tracking.
   
2. Manual AF point selection, which works just like spot AF, just with a larger AF point.
   
3. Single expanded AF point selection, where the camera starts tracking with the selected point but then can hand over to one of the (two to four) expansion points, if the main point looses track of the subject.
   
4. Fully automatic AF point selection, in which case you now, for the first time, can select whichever point you prefer tracking to begin with, and then the camera can automatically hand over focus to any of the other 18 points, if the main one looses track of the subject.
   
5. Zone AF, in which case it seems that even in Servo AF, the camera will pick the point(s) it finds best (a strategy which could be described as pseudo-random) to start tracking with, and then hand over to any other point inside the zone.

I only received my 7D a couple of days ago.

So far i've shot a rugby match during which i used the Single point with expansion focus mode. This worked great for large subjects close up and far away from me.

I've also been out shooting birds which is my main interest. For fairly static birds i've been trying all the focus modes out except full auto which is disabled. I found that Spot, Single or Single/expansion all work great.

For birds in flight I've found that using the Zone, set to centre is better for me as i struggle keeping just one foucs point on my subject.

I've not used it enough to to fully get used to it but it does seem random on which point in the zone starts tracking the subject, quite cool to see the focus point move about as it tracks though.

Having said that I did get some great shots back using the Zone Af

But as many posters on here have said it is going to take some time to get used to the AF and its many options.

On the 7D overall, coming from a 20D, I have to say that i am mighty impressed.

Expansion mode roughly matches what I've used on my 5D's (although the expansion AF points on the 5D and 5D2 are "invisible" and only surround the center point). It has been pretty successful, though on the 5's, you are confined to the center AF point as a starting point.

I still have to experiment with all the modes on the 7D but I do like the expansion focus mode so far.

Zone for BIF is fine if the background is clear.