Orientation Locking Knob; Tripod Mount - Canon EF 300mm f/4L IS USM Instruction

7. Using the Tripod Mount
Adjusting the Revolving Mount
You can loosen the orientation lock-knob on the tripod mount to allow it to rotate as needed to fit a
particular camera model for switching between vertical and horizontal positions.
Detaching
Use the following procedures to remove and attach the tripod mount.
Loosen the orientation
locking knob.
If the foot of the tripod mount overlaps the switch, loosen the orientation locking knob on the tripod mount to
move the foot.
Rotate the tripod mount and
align the mounting indicator
on the tripod mount with the
one on the lens.
Slide off the tripod collar
away from the rear of the
lens.
ENG-9