Canon EOS-1DX MARK II Settings Manual page 79

Up to 41-point AF cross focusing is possible
even using lenses with a maximum aperture
f-number of f/4. In addition, f/8 AF is possible
with all 61 AF points
The AF system of the EOS-1D X Mark II has many
attractive features such as the high level of composition
freedom with 61 different AF points, AF area selection
modes that utilize the merits of the multi-point AF
system, and implementation of the AF Configuration
Tool which takes advantage of the improved AI Servo AF.
In addition to these, is the high precision and improved
tracking performance of each AF point to capture both
still and moving subjects.
The same as the EOS-1D X, most f/2.8 – f/4 lenses can
utilize the high-performance 41-point cross-type AF
points. Thank to the numerous high precision f/2.8 and
f/4 AF points, focusing with higher precision than before
when using larger aperture lenses can be achieved.
Also, on the EOS-1D X the only f/8 supported points
were the center point the center point, and AF point
expansion to the four points on the top, bottom, and
left, so being able to use all 61 points is a main feature.
Even with the condition of a maximum aperture value of
f/8 using an extender, etc., it is now possible to use all
AF points with high precision focusing. Please note that
f/8 AF performance at all 61 AF points does depend
upon using specific compatible Canon EF lenses and
Canon version III tele extenders.
79