Canon EOS-1D X Mark III DSLR Camera (Body Only) - Manual (Page 378)

Subject switching
• Initial priority
Tracks the subject initially determined for AF, to the extent possible.
• On subject
Generally tracks the subject initially determined for AF. May switch to other subjects
if the current subject is no longer suitable for AF.
• Switch subject
Switches to track other subjects in response to shooting conditions.
Caution
Precautions when set to [Initial priority]
The camera may not be able to continue tracking subjects under some subject
conditions.
• If subjects move vigorously
• If subjects face a different direction or change their posture
• If AF points stray from subjects, or if subjects are hidden behind
obstructions and you can no longer see them
With [ AF priority (People) ] set to [ Enable ], the camera may switch to the face
or head, depending on subject conditions.
Subjects selected by touch are tracked to the extent possible, regardless of the
option selected in [
Subject tracking settings ].
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