Canon EOS-1DX MARK II Settings Manual page 107

Whether you shoot sports or portraits, wildlife or fashion,
it's common to quickly rotate the camera from horizontal
to vertical orientation.
The EOS-1D X Mark II is equipped with an abundance
of AF points to choose from — 61 points to be exact.
This provides a high degree of freedom when composing
shots. However, one downfall is that, when the
uppermost left AF point is selected for shooting while
the camera is held in the horizontal position, when the
grip is switched to the vertical position, the AF point ends
up in the bottommost lower left of the screen. If you
want to keep the entire body of the athlete in the frame
while focusing on their face, you must choose another
AF point.
In situations like this, AF point settings for each
position are especially useful. By selecting [Separate AF
pts: Area+pt] from [Orientation linked AF point],
individual settings for each of the AF area selection
modes and the manually selected AF points can be
stored in the camera memory.
In the previous case, for example, if you set the center
upper edge AF point beforehand when in the vertical
position with the grip at the top, it is possible to have
the AF point line up with the position of the face
instantly when switching from the horizontal to vertical
position.
107