Graflex 35 - img011

SETTING
THE
DIAPHRAGM
The right combination
of shutter speed and
lens opening is most
important. You will find
excellent
exposure in-
formation in the in-
struction sheet packed
with the film. Use it
carefully, since it is an
accurate, dependable
guide.
The lens opening is controlled by the diaphragm
within the lens and is measured in Hf / stops." The
larger the f/ stop number, the smaller the dia-
phragm opening and the less light admitted to the
film, and vice versa. ( The opening 8 lets in twice
as much light as 11; 5.6 twice as much as 8, and
so on. ) To set, simply move the diaphragm lilVer
until the red line of its pointer lines up with the
black line opposite the f/ stop number you select.
NOTE: Lens aperture, diaphragm opening, stop
opening, f/ stop, f/ number and similar phrases are
often used synonymously (although inaccurately).
Any change in the diaphragm setting requires a
compensating change in the shutter speed if identi-
cal exposure is to be obtained. For example, f/8
changed to f/11 requires the change in shutter
speed from 1/ 50th of a second to 1/ 25th, unless
different exposure is desired.
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