Canon EOS-1DX Af Setting Manualbook page 65

Auto selection of 61 AF points
When using [Auto selection of 61 AF
points] during [AI Servo AF], focusing
will start from the manually selected AF
point, the camera will the automatically
change the AF point selecting from all
61 points as the subject moves.
AI Servo AF with all 61 points used for
automatic tracking
One-Shot AF
AI Servo AF
When using [One-Shot AF], a single AF point is selected
automatically from the 61 points. When using [AI Servo
AF], AF starts from the manually selected AF point and
then selects the most appropriate from all 61 points.
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