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Chapter 2 Camera Handling, Care, and Support
Copyright Goodheart-Willcox Co., Inc.
bright lighting conditions, for example, the
image can appear overexposed or “washed out.”
For critical evaluation of exposure, the display
can be switched to show a histogram and image
information.
Histogram/Exposure Display
The histogram is a bar graph showing all
of the tonal values of an image, Figure 2-15.
The graph is composed of 256 bars or columns
that represent the number of tones in an 8-bit
image. Ranging from pure black at the left to
pure white at the right, each bar represents
the number of pixels of a specific value in
the image. The result is a mountain range
appearance with peaks and valleys—peaks
indicate a large number of pixels, while valleys
are indicators of few or no pixels.
Learning to read the histogram is the key to
evaluating your exposures and making necessary
adjustments to obtain the best possible image.
This topic is discussed in Chapter 10, Making
Exposure Decisions.
White Balance
The human eye compensates for the color
of light, but a camera does not. To capture and
display colors accurately, film photographers
load their cameras with either daylight-
balanced (outdoor) or tungsten-balanced
(indoor) film. Digital camera users achieve
the same results by selecting a white balance.
By adjusting the camera’s response to make a
white object appear white under specific light
conditions, all other colors seen under that
lighting will be shown accurately.
Most digital cameras allow you to select
automatic white balance (AWB) or one of a
number of presets for such conditions as sunlight,
shade, tungsten lighting, fluorescent lighting, or
flash. See Figure 2-16. AWB or one of the presets
provides good results in most situations.
Jack Klasey/Goodheart-Willcox Publisher
Figure 2-14. A pivoting LCD can be used as a viewfinder
for situations such as shooting over a crowd, capturing
flowers silhouetted against the sky, or even making
“around the corner” photographs.
A B
Jack Klasey/Goodheart-Willcox Publisher
Figure 2-15. A camera’s histogram display is an essential tool for the digital photographer. A—The display is a bar
graph showing all the tones in the image, allowing you to evaluate exposure and make any needed changes. B—Some
cameras allow you to select an additional histogram display that shows the values for each the three primary colors.