Nikon D300 User Manual page 667

is too great to be captured by a digital sensor but is exposed in
such a way that we can get a usable photo later.
Notice in Figure 9-19
dark detail is lost. But look to the right side of the histogram
and notice how the light values are not clipped off. The
camera recorded all the light values but lost some dark values.
Since our eye sees this as normal, this image looks okay.
Figure 9-19. Cabin picture with correct exposure but dark
shadows, and its histogram
If we were standing there looking at the cabin ourselves, our
eye would be able to see much more detail in the front porch
area. But the camera just can't record that much light range. If
we want to get a bit more detail in the shadows than this
image seems to contain, we can do it. Normally, a camera
does not give us enough control to add light values on the fly,
so we use the histogram to get the best possible exposure and
then adjust the image later in the computer. Some cameras
can be profiled to capture light ranges more effectively in one
direction or the other, but when you push one area, the
opposite area must give. So, we need a way to take all this
light and compress it into a more usable range.
how the dark values are clipped off and
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