Nikon D300 User Manual page 659

worth spending time to understand the histogram. It's not as
complicated as it looks.
I'll try to cover this feature with enough detail to give you a
working knowledge of how to use the histogram to make
better pictures. If you are deeply interested in the histogram,
there is a lot of research material available on the Internet.
Although this overview is brief, it will present enough
knowledge to improve your technique immediately.
Light Range
The D300(S)'s sensor can only record a certain range of light
values—about 5 to 7 usable EV steps. Unfortunately, many of
the higher-contrast subjects we shoot can contain over 12
stops of light values. This is quite a bit more than it is
possible to capture in a single exposure. It's important to
understand how your camera records light so that you can
better control how the image is captured.
Look at Figure 9-14 closely. The gray rectangular area
represents an in-camera histogram. Examine it carefully!
Think about it for a minute before reading on.
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