Canon EOS 10D - Manual (Page 66)

66
Selecting AF Mode
AI Servo AF for Moving Subjects
While you press the shutter button
halfway, the camera focuses continu-
ously.
•
This AF mode suits moving subjects when the
focusing distance keeps changing.
•
With predictive AF∗, the camera can also focus
track a subject which steadily approaches or
retreats from the camera.
•
The exposure settings are set immediately before
the image is captured.
•
When focus is achieved, the focus confirmation light < ●> in the viewfinder will not
light and the beeper will not sound.
•
If the focus confirmation light < ●> in the viewfinder blinks, it means focus has not
been achieved.
•
Focus lock cannot be used.
∗
Predictive AF
If the subject approaches or retreats from the camera at a constant rate, the camera tracks the
subject and predicts the focusing distance immediately before the image is captured. This is
for obtaining correct focus at the moment of exposure.
•
When the AF point selection is automatic, the camera first uses the center AF point to focus.
If the subject moves away from the center AF point, focus tracking continues as long as the
subject is covered by another AF point. The active AF point will not flash in red.
•
With a manually selected AF point, the selected AF point is used for predictive AF.
With C.Fn-04-2, holding down the < > button will temporarily stop the AF operation in
the AI Servo AF mode. (
→p.146)
AI Focus AF for Automatic AF Mode Switching
The AI Focus AF mode switches automatically from
One-Shot AF to AI Servo AF if the subject starts to
move.
If focus is achieved in the One Shot AF mode and the
subject starts to move continuously, the camera will
detect the movement and switch automatically to AI
Servo AF to focus track the subject.