Canon EF135mm F2L USM Instruction page 10

11. Filters
(sold separately)
A filter can be attached by
screwing it on the front of the
lens.
When a circular polarizing filter
is required, use Canon's
polarizing filter PL-C. The
polarizing filter cannot be
rotated unless the hood is
detached or retracted first.
ENG-9
12. Extenders
Separately-sold Canon
Extenders EF 1.4 II and EF
2 II can be attached to any of
the four lenses. The extenders
increase the lens' focal length
by 1.4 and 2 respectively,
and the maximum aperture
respectively decreases by 1
stop and 2 stops. The
autofocusing speed also
decreases to maintain proper
AF control.
When Extender EF 1.4
•
EF 2 II is attached to the EF
400 mm f/5.6L USM lens, the
lens switches automatically to
manual focus. Also, when
Extender EF 2 II is attached
to the EF 300 mm f/4L USM
lens, the lens switches
automatically to manual
focus.
II or