Canon TS-E24mm F3.5L Instruction Manual page 12

5. Rotation
ENG-10
The rotation function enables you to change the direction of tilt or
shift by rotating the tilt-shift mechanism.
With the lens mounted on the camera, push the rotation lock release
button towards the mount and then turn the tilt-shift mechanism.
●
The mechanism can be rotated through ±90°. The lens clicks every 30° and
locks in place in the 90° position.
●
When rotating the lens, set the tilt and shift scales to the "0" position.
●
Note that rotating the tilt-shift mechanism quickly while pressing on the
rotation lock release button may cause the shift lock knob to strike your
fingers.