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CAMERA SENSITIVITY – ISO
Five settings can be selected for camera sensitivity: Auto, 100, 200, 400, and
800; the numerical values are based on an ISO equivalent. ISO is the standard
used to indicate film sensitivity: the higher the number, the more sensitive the
film. See setting the function dial section on page 44 to change the ISO setting.
The auto setting automatically adjusts the camera sensitivity to the light condi-
tions between ISO 100 and 400.When the flash is activated and camera sensi-
tivity is set to auto, the ISO value is set between ISO 100 and 200.When any other setting than auto
is used, “ISO” will appear on the data panel, and “ISO” and the set value will be displayed on the
monitors.
Photographers can select a specific sensitivity setting. Like grain in silver-halide film that increases
with speed, noise increases with sensitivity in digital imaging; an ISO setting of 100 will have the
least noise and 800 will have the most noise. A change in ISO also affects the flash range (p. 66); the
higher the ISO, the greater the range.
As the ISO value doubles, the camera sensitivity doubles; changing the ISO between 100 and 200,
200 and 400, or 400 and 800 changes the camera sensitivity by one stop or 1 Ev (p. 151). A change
between 100 and 800 changes the camera sensitivity by a factor of 8 or three stops. High ISO set-
tings (400, 800) will allow the photographer to hand hold the camera in low-light conditions without
the need of a flash.
When making bulb exposures (p. 53), noise can be more pronounced because of the unusually
long exposure times, especially at 400 and 800 ISO. When making long bulb exposures of 20 to
30 seconds, a camera sensitivity setting of 100 or 200 will produce excellent results. At higher
ISO settings, using shorter exposure times (8 – 16 seconds) will reduce the effect of noise. With
long exposures at high ISO settings, noise from interference may be noticeable.
Camera Notes