Nikon D300 User Manual page 218

Normally, you will set your camera to a particular ISO
number, such as
light gets darker, or in the deep shade, you might increase
ISO sensitivity
absolutely must get the shot,
work nicely. Here are a few scenarios:
▪ Scenario # 1: Let's say you're a photojournalist and
you're shooting flash pictures of the president as he
disembarks from his airplane, walks into the terminal,
and drives away in his limousine. Under these
circumstances, you will have little time to check your
ISO settings or shutter speeds and will be shooting in
widely varying light conditions.
▪ Scenario # 2: You're a wedding photographer in a
church that doesn't allow the use of flash. As you follow
the bride and groom from the dark inner rooms of the
church, out into the lobby, and finally up to the altar,
your light conditions will vary constantly. You have no
time to deal with the fluctuations in light by changing
your ISO since things are moving too quickly.
▪ Scenario # 3:
You're at a party, and you want some great pictures. You
want to use flash, but the pop-up Speedlight may not be
powerful enough to reach across the room at low ISO
settings. You really don't want to be bothered with
camera configuration at this time but still want some
well-exposed images. Light will vary as you move
around the room, talking and laughing and snapping
pictures.
200 or 400, and shoot your images. As the
to continue taking handheld images. If you
ISO sensitivity auto control
218
will