AF Point Expansion:

This is a feature that’s been available on EOS models with the 45-point AF system, like the EOS-1D series cameras. Now, for the first time, it’s available to users in a mid-range model. AF Point Expansion allows the user to manually choose any one AF point to be the primary point he or she wants to use to focus on their subjects. Again, it can be the center point, or any off-center point. But now, additional surrounding points are active, and if the primary point for any reason loses sight of the subject, or can’t find sufficient detail, the surrounding AF points are immediately called-in to assist in focusing upon the subject. This occurs whether you’re shooting a stationary subject in One-Shot AF mode, or tracking a moving subject in AI Servo AF. In fact, AF Point Expansion can be very useful for sports photography and other moving subjects, especially if there’s concern that your AF point may pick up plain, solid areas of a player’s uniform, an animal’s body, and so on.

The number and location of surrounding AF points will vary, depending upon which primary AF point you’ve manually selected. Also, there’s no way to add or subtract these additional surrounding AF points when in AF Point Expansion mode. Fortunately, the camera’s intelligent viewfinder does display the added expanded points — your primary AF point appears as one rectangle, while during selection, the added expanded points appear with the standard AF box and smaller spot AF box. So it’s never a mystery where these added points are, during selection and shooting.

Again, during actual shooting, the camera will always try to focus using the one primary AF point you’ve chosen. So it remains an effective tool when you want the camera to focus on one area whenever that’s possible — for example, a photographer shooting tight shots of a horse race, with the animal running straight into the camera, could put focus with his or her long telephoto lens right on the horse’s nose as it charges down the straightaway. But if for whatever reason that single point isn’t able to track the subject, the surrounding points instantly kick-in, lessening the chance of losing focus on the subject. But if one of the surrounding AF points is used, it will change from a tiny spot-only rectangle in the finder to a full AF point.

Accessing AF Point Expansion follows the same pattern: first, press the rear AF point select button, then press the M.Fn button. When you see a display like this, you’re in AF Point Expansion mode. Now, turn either dial, or use the Multi-controller, to move your primary AF point where you’d like it to be.

For a more in depth information on the EOS 7D Auto Focus System, please click on the following link: http://www.learn.usa.canon.com/resources/articles/2011/whats_news_eos7d_article.shtml