Canon EOS-1DX MARK II Settings Manual page 4

AI Servo AF III +
New algorithm of
Improved support capability for difficult to
capture movement of subjects that come
close, then move away
The main improved point of the AF system on the EOS-
1DX Mark II is the use of AI Servo AF III + with an even
more sophisticated predictive AF algorithm. For shooting
sports and wildlife with erratic movement, AI Servo AF III
capable of stable subject tracking was included in the
EOS-1D X. In cases where obstacles may obscure the
subject, and when the subject moves away from the AF
point briefly, it is equipped with performance capable of
tracking the subject.
With the AI Servo AF III + included this time, support is
improved for subjects that approach then move away
suddenly, that had been difficult to focus on up until
now. Movement such as motorcycles and racecars that
approach corners, to figure skating and speed skating.
Even in cases like these, AI Servo AF III+ on the EOS-1D
X Mark II is capable of continuously tracking subjects that
move away from the camera.
Handling is improved for a variety of movement, with
the refined AF algorithm AI Servo AF III + .
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