70AF Point Activation Area C.Fn-17C.Fn-17 can be set to expand the AF point’s activation area to include more than one activeAF point. (→p.137) See “Setting a Custom Function” on page 132.• C.Fn-17-1 Expanding the activation area to 7 points(→p.137)This larger activation area makes it easier to focus subjects moving irregularly.• The expanded AF point activation area is notdisplayed in the viewfinder.• When focus is achieved in the One-Shot AF mode,the selected AF point and the AF point(s) achievingfocus will light.C.Fn-17-1: Selected AF point.: AF points in expandedactivation area.• C.Fn-17-2 Expanding the activation area to 7 or 13 points automatically(→p.137)As shown below, the AF point activation area expands automatically to 7 or 13 points depend-ing on the lens focal length, AF mode, and the subject’s speed in the AI Servo AF mode. Thisis effective when the subject’s movement is unpredictable.C.Fn-17-2AF Mode Lens Focal LengthShorter than 300mm 300mm or LongerOne-Shot AFAI Servo AFThe activation area does not expandautomatically. The activation area expands by one point.For a slow-movingsubjectFor a fast-movingsubjectFor a slow-movingsubjectFor a fast-movingsubjecta a∗ To set the Custom Function, see “Setting a Custom Function” on page 132.
