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Guide to exposure control
Exposure is the amount of light that
reaches the film through the lens. It is
controlled by the length of time the
shutter is open (shutter speed) and
the size of the opening in the lens
(lens aperture).
The shutter stays open for the length
of time indicated on the ring. The num-
bers signify fractions of a second; thus,
60=1/60 sec., 4=1/4 sec., 1-1 sec., etc.
Each shutter speed will admit either
twice as much or half as much light
as the one next to it on the ring.
The lens opening can be made larger
or smaller. The size of the opening is
measured in f-numbers, which are
marked on the lens ring. The highest
f-number in-dicates the smallest open-
ing; the lowest f-number indicates the
largest opening.
Each lens opening will admit either
twice as much or half as much light as
the one next to it on the ring. Thus,
changing from f/11 to f/8 will double the
exposure; changing from f/11 to f/16 will
cut the exposure in half.
Operations 7
Exposure correction
To increase exposure (make pictures
lighter), use a longer exposure time
(slower shutter speed), or a larger lens
aperture (lower f-number). To decrease
exposure (make pictures darker), use a
shorter exposure time (faster shutter
speed), or a smaller lens aperture
(higher f-number).
Shutter speeds
125
60
30
o
Darken / Lighten
Lens openings
4.5
5.6
8
o
Lighten / Darken
Note: When using an electronic flash
system, the shutter is set at a specific
speed. A control on the power supply is
used to adjust the light output of the
lamps to control the exposure. (See the
instructions supplied with the flash unit.)
15
8
4
2
11
16
22
1
o
32
o
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