Canon FT - Focusing Scale Interpretation

Infr ared I ndex" R"
I nd i cato r ( oran ge li ne )
Dist a nce Sc ale
Distance Scale
The distance scale indicates the distance between the
focused subject and the film plane. The scale is neces·
sary for checking the depth · of · field, for flash and infrared
photographies .
• The correct posit ion of the scale is in the center of
each value. For ex ample , the correct position of a two -
dig it value is the center of the two figures.
Infrared Index" R "
For i nfrared photography, correction of the distance scale
is necessary because the focal point slightly deviates from
ordinary photography. Focus first in the ordinary manner,
then adjust that distance scale to the infrared mark " R ".
For instance, if the distance scale reads 10m after focus-
ing, merely shift the 10 scale to .. R" position.
The position of .. R" on the FT is based on using film
with the highest wave- length sensitivity figure of 800m ,u ,
such as Kodak IR 135 film and Wratten 87 filter .
Film Plane Indicator
In case the focusing is done by actual measurement,
measure the distance from the film plane indicator and
interpret the measured distance on to the distance scale.
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