Canon AE-1 User Manual
Page 60
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Distance Scale
The disieoce scale is for distances
measured from the film plane. This scale is
not generally used except for confirming the
depth*of*field. performing guide number
calculations in flash photography« or photo
graphing with infrared film.
Read i^enjigit distances in the middle of
the number marked on the scale. Two-digit
distances should be read at the point in the
middle of the two digits.
DoptfK)f-Field Scale
You can determirw the depth*of*field by
checking the depth*of*lield scale and the
distance scale on the lens barrel. Both are
closely interrelated.
Infrared Irsdex Mark
The red dot infrared index mark engraved
on the lens barrel is a focusing correction
index mark for infrared film. Because infrared
light rays have longer wavelengths, they focus
on a plane slightly behind that of ordinary
visible l»ght rays. Therefore, it is necessary to
slightly modify the normal method of focus
ing the lerH. After focusing the same as usual«
note the tiny red dot engraved on the lem
barrel
fo % %
to the right of the distance index
and turn the focusing ring slightly to align the
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