Canon EOS-1D X Mark III Af Setting Manualbook page 66

[Subject tracking settings]
[Subject tracking settings] [Subject switching]
[Subject switching: Disable]
Performs tracking without shifting to another subject. It is
effective when photographing one person at a time.
However, continuous
depending on subject.
[Subject switching: Enable (slow)]
This is the basic setting to continuously track the detected
subject. If the camera determines that it is not suitable for
tracking, it may switch to another subject.
[Subject switching: Enable]
This setting makes it possible to shift more actively to other
subjects. It is effective when you want to switch the target
athlete frequently.
tracking may not be possible
66 66