So, I'll get to my question. I would certainly love to have 61-point AF, but if the 6D AF is equivalent to or better than the 40D AF, that'd probably be good enough for me. Has anyone upgraded from a 40D to a 6D who could share some thoughts? How are the outer points? The 40D has 9 cross-type, the 6D has only one. In actual practice, has that been noticeable?
Thanks so much!
I haven't done exactly that upgrade. I have a 5DII I upgraded from an older rebel (the former is pretty similar to the 6D). The outer points are usable, but I usually go with the center and focus-recompose.
Having more AF points and some more advanced features for AF tracking would be useful for sports shooting, but for one shot AF mode it works quite well. I've even found servo quite good with the center point -- I recently took shots of the finish line in a 5K race (subject running straight at the camera) and didn't bother with several shots per subject and it turned out I didn't need to. Keep rate was very good. I used center point with servo. Most of the misses were "user error" (subject "fell off" the AF point) which could have largely been fixed by taking more shots. The lens by the way was the 135L.
In your case it seems like a no-brainer -- your overall system will be much more usable if you spend the extra money on glass (and a flash if you don't have one yet)