Canon EOS-1DX MARK II Settings Manual page 71

Begin focusing on the subject with an AF
point near the center, and then by moving the
camera to the left, you can compose a photo
with space on the left side of the frame.
Shooting started by pinpointing focus on the leader of a
cycling road race with a manually selected AF point.
While taking continuous shots, the camera was moved
to the left so the following cyclists on the left of the
leader are rendered beautifully out of focus in the
background.
71