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H O W TO DISMOUNT AND MOUNT LENS
TO DISMOUNT LENS
Unscrew the lens, which may be in either extended or
retracted position, by grasping its b;tsc. First loosen the
lens by a slight jerking motion, then unscrew gently.
Do not oil the thread of the lens or tamper with the
lens in any way. Always keep the lens flange shaded.
TO MOUNT LENS
Holding the lens by its base, find the thread of the
screw by turning the [ens slightly in a counter-clockwise
direction, then screw clockwise into the flange until light.
DO NOT ATTEMPT TO T I G H T E N THE LENS INTO
THE FLANGE
BY GRASPING ANY OTHER PART
BUT THE BASE.
I N F R A R E D
M A R K
Infrared Mark is used only for infrared photography. After focusing in the usual manner, read
the object distance scale of the tens, and then turn the lens so that the object distance is exactly
opposite the " R " index mark. The lens is now focused for infrared photography.
Infrared mark on any Canon lens is situated
in a position where it will offer the best re-
sult by using infrared film and infrared
filter (such as Kodak IR 135 and Wratten
Filter No.87).
both having a maximum
sensitivity at a wave length of approximately
8000A. Therefore, it is appropriate to shift
about 1/3 of the amount to " R " when
using, say, Kodak Plus X or
regular-
panchromatic film with a Wratten filter or
about No. 25.
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