Canon EOS 5D MARK IV Instruction Manual page 146

3 Customizing AF FunctionsN
AF area selection method
You can set the method for changing the AF area selection mode.
When [S9Main Dial] is set, use the <9> to move the AF point
horizontally.
Orientation linked AF point
You can set the AF point or the AF area selection mode + AF point
separately for vertical shooting and horizontal shooting.
144
:S9 M-Fn button
After you press the <S> button,
pressing the <p> (AF area selection)
button or <B> button changes the
AF area selection mode.
:S9 Main Dial
After you press the <S> button,
pressing the <p> (AF area selection)
button or 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.
AF4
AF4