Konica Minolta DiMAGE_A2 Manuel D’Utilisation

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Photography can be a rewarding pursuit. It is a broad and disciplined field that can take years to
master. But the pleasure in making photographs and the joy of capturing a magical moment cannot
be compared. The guide is an introduction to some basic photographic principles.
A short Guide to Photography
109
The lens aperture controls not only exposure, but also depth of
field; the area between the closest object in focus and the furthest
object in focus. The larger the aperture value, the greater the
depth of field and the longer the shutter speed needed to make
the exposure. The smaller the aperture value, the shallower the
depth of field and the faster the shutter speed needed to make
the exposure. Usually landscape photographs use a large depth
of field (large aperture value) to keep the foreground and back-
ground in focus, and portraits use a shallow depth of field (small
aperture value) to separate the subject from the background.
Depth of field also changes with focal length. The smaller the
focal length, the greater the depth of field; the longer the focal
length, the shallower the depth of field. 
The shutter controls not only exposure, but also the ability to stop
motion. Fast shutter speeds are used in sport photography to
stop action. Slow shutter speeds can be used to show the flow of
motion such as water cascading over a waterfall. The use of a tri-
pod is recommended with slow shutter speeds.
The change in aperture and shutter speed is not apparent in the
live image. For critical work, take a test photograph  and view the
result in Quick View (p. 40).