Pentax Optio A40 Operating Manual page 58

Using Histogram
A histogram is a graph showing the
brightness of an image on the horizontal
axis and the number of pixels on the
vertical axis (distribution chart of the
brightness). The histogram will help you
detect the brightness of the image you
have taken. For instance, the graph
peak tends to appear on the left side for
Brightness
a darker image, and the graph peak
(Dark) (Bright)
tends to appear on the right side for a
brighter image.
In general, when the exposure metering of your image is well-balanced,
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the graph peaks tend to appear in the middle.
On the contrary, when the exposure metering of the subject is imbalanced,
that is with dark areas and/or bright areas, the peaks will appear on the
sides rather than in the middle.
Dark Neutral Bright
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