Auto Focus

[Richard Lane]

Back Button Focus all the way!

It's great to separate AF and tracking from the shutter.

The 7D had AI Focus too, and it's a hybrid mode and hybrids aren't exactly better than their full functioning counterpart. It's usually better if you decide as opposed to the camera.

Once you get used to Back-button focus, then you'll have the best of both worlds, when in AI servo if you hold the AF-on button in, then you'll continue to track, and once you release the button then you will have AF lock. You'll probably find that you'll use One Shot less after the change.

http://learn.usa.canon.com/galleries...utorials.shtml (it's the 5th tutorial in the row)

One thing I would recommend is to not use it at one of your weddings for the first time, because I guarantee you that you will forget to focus on some shots. It happens to everyone. It's like falling over on a bike with clipped pedals for the first time, everybody does it at least once. So, make the change well before you need to use it critically, and by then it will become second nature.