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❚❚Auto ISO Sensitivity control
If Off is chosen for Auto ISO sensitivity control in P, S, A, and M modes, ISO sensitivity
will remain fixed at the value selected by the user (049).
When On is chosen, ISO
sensitivity will automatically be adjusted if optimal exposure can not be achieved at
the value selected by the user (ISO sensitivity is adjusted appropriately when the
flash is used).
The maximum value for auto ISO sensitivity can be selected using the
Maximum sensitivity option in the Auto ISO sensitivity control menu (choose
lower values to prevent noise (randomly-spaced bright pixels, fog, or lines, but note
that if the ISO sensitivity selected by the user is higher than that chosen for
Maximum sensitivity, the value selected by the user will be used instead; the
minimum value for auto ISO sensitivity is automatically set to ISO 100)).
In modes P
and A, sensitivity will only be adjusted if underexposure would result at the shutter
speed selected for Minimum shutter speed (1/2000–1s, or Auto; in mo des S and M,
sensitivity will be adjusted for optimal exposure at the shutter speed selected by the
user).
If Auto (available only with CPU lenses) is selected, the camera will choose the
minimum shutter speed based on the focal length of the lens (auto shutter-speed
selection can be fine-tuned by highlighting Auto and pressing 2 ; for example, faster
values can be used with telephoto lenses to reduce blur).
Slower shutter speeds will
be used only if optimum exposure can not be achieved at the ISO sensitivity value
selected for Maximum sensitivity.
When On is selected, the viewfinder shows ISO-AUTO and the
information display ISO-A.
These indicators flash when
sensitivity is altered from the value selected by the user.
AMaximum Sensitivity/Minimum Shutter Speed
When auto ISO sensitivity control is enabled, the ISO sensitivity
and shutter speed graphics in the information display show the
maximum sensitivity and minimum shutter speed.
AAuto ISO Sensitivity Control
Noise (randomly-spaced bright pixels, fog, or lines) is more likely at higher sensitivities.
Use
the High ISO NR option in the shooting menu to reduce noise (0153).
Note that ISO
sensitivity may be raised automatically when auto ISO sensitivity control is used in
combination with slow sync flash modes (available with the built-in flash and the optional
flash units listed on page 205), possibly preventing the camera from selecting slow shutter
speeds.
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Maximum sensitivit
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