Canon EOS-1D X Mark II DSLR Camera (Body Only) - Manual (Page 104)

Lenses and Usable AF Points
104
Autofocusing with 61 points is possible. All the AF area selection modes
are selectable.
: Cross-type AF point. Subject
tracking is superior and high-
precision focusing is achieved.
: AF points sensitive to horizontal lines.
Autofocusing with 61 points is possible. All the AF area selection modes
are selectable.
If an Extender is attached (Extender compatible lenses only) and the
maximum aperture is f/8 (greater than f/5.6 but not exceeding f/8), AF
will be possible.
: Cross-type AF point. Subject
tracking is superior and high-
precision focusing is achieved.
: AF points sensitive to horizontal lines.
Group E
Group F
If the maximum aperture is slower than f/5.6 (greater than f/5.6 but not
exceeding f/8), focus may not be achieved with AF when shooting low-
contrast or low-light subjects.
If the maximum aperture is slower than f/8 (exceeding f/8), AF is not
possible during viewfinder shooting.