Canon EOS-1D X Instruction Manual page 101

AF area selection method
You can set the method for changing the AF area selection mode.
→ Main Dial] is set, use the <9> to move the AF point
When [
horizontally.
Orientation linked AF point
You can set the AF point or a combination of AF area selection mode
and AF point separately for vertical shooting and horizontal shooting.
3 Customizing AF Functions
→ M-Fn button
After you press the <S> button, the AF
area selection mode changes each time
you press the <B> button.
→ Main Dial
After you press the <S> button, turning
the <6> dial changes the AF area
selection mode.
: Same for both vert/horiz
The same AF area selection mode and
manually-selected AF point (or Zone) are
used for both vertical shooting and
horizontal shooting.
101