Canon EOS-1D X Mark II DSLR Camera (Body Only) - Manual (Page 130)

3 Customizing AF Functions
130
You can change the number of manually selectable AF points. With
Zone AF, Large Zone AF, or Automatic selection AF set, AF will be
performed with the selected AF area selection mode (Zone AF, Large
Zone AF, or Automatic selection AF) regardless of the [
Selectable AF
point ] setting.
: All points
All AF points will be manually
selectable.
: Only cross-type AF points
Only cross-type AF points will be
manually selectable. The number of
selectable AF points will vary
depending on the lens used.
: 15 points
Fifteen major AF points will be
manually selectable.
: 9 points
Nine major AF points will be manually
selectable.
Selectable AF point
With a lens from groups G to K (p.105-108), the number of manually
selectable AF points will be lower.
Even with settings other than [ All points ], AF point expansion (manual
selection ), AF point expansion (manual selection, surrounding points),
Zone AF, and Large Zone AF are still possible.
When you press the < S > button, the AF points that are not manually
selectable will not be displayed in the viewfinder.