Canon EOS-1D X Mark II DSLR Camera (Body Only) - Manual (Page 108)

Lenses and Usable AF Points
108
AF is possible with the center AF point and the adjacent AF points
above, below, on the left, and on the right. Only the following AF area
selection modes are selectable: Single-point Spot AF, Single-point AF,
and AF point expansion (manual selection ).
: Cross-type AF point. Subject
tracking is superior and high-
precision focusing is achieved.
: AF points sensitive to horizontal lines
(left and right AF points adjacent to
the center AF point) or vertical lines
(top and bottom AF points adjacent
to the center AF point). Not manually
selectable. It works only when AF
point expansion (manual
selection ) is selected.
: Disabled AF points (not displayed).
Group K