Datasheet

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Chapter 12: Taking Great Pictures
Microsoft Digital Image Standard User’s Manual
Aperture
The aperture is the opening through which light passes to reach the film, or, in
digital cameras, the image sensor. Aperture is measured by
f-number, where
a specific setting is called an
f-stop. With f-stops, a low number, such as f/4,
represents a wider opening that lets in more light. A small aperture, such as
f/16, lets in significantly less light.
Some cameras have a fixed aperture that can’t be adjusted. If you’re adjusting
the aperture yourself, a setting of f/8 is a good place to start, since it gives you a
fairly wide zone of sharpness.
If your camera allows you to adjust the aperture, use the settings to regulate the
depth of field in your picture. Depth of field refers to the zone in your photo that
is in acceptably sharp focus. A wide aperture gives you a shallow depth of field,
while a small aperture allows a very deep zone—maybe even everything in the
picture—to be in focus.
Imagine pointing your camera down a set of railroad tracks which go all the
way to the horizon. With a wide aperture, like f/2.8, if you focus on a railroad
tie a short distance away, only a few of the other ties are in sharp focus. With a
narrow aperture, like f/22, many more of the ties are in focus, even those quite
a distance from your main focal point.
A wide aperture will give you a short depth of field, as illustrated in the photo on the left,
where only the eagle is in focus. The photo on the right was taken with a small aperture,
so almost everything is in focus.
Program modes
If your camera offers
program modes for
specific types of
pictures like portraits
or action shots, read
your camera’s manual
to find out the aperture
settings used for those
modes.