Canon EOS-1DX MARK II Settings Manual page 65

For larger subjects or subjects that move over
a larger area
Zone AF
Photo
Touch to
enlarge
image
A photo of a moment of action as runners jump over
hurdles shot with [Zone AF], using AI Servo AF. In order
to focus on the closest runner, as well as compose the
runner in the back on the right of the frame, this shot
was taken by selecting the upper left zone.
[Zone AF] not only focused on the nearest runner, but
upon the nearest surface of that runner, within the active
zone of AF points. In AI Servo AF, [Zone AF] will
continually update and display the actual AF points being
used, to keep the nearest part of a subject in focus.
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