Graphics Reference
In-Depth Information
captures the image at the moment the shutter is opened, a second stage
occurs during which the image is downloaded to a memory card inside the
camera, where the image is then stored. Unlike film, the CCD does not retain
the image forever but is cleared and is then ready to capture the next image.
Film Speeds
Traditional photographic film still meets the needs of a certain part of the
market, though digital photography has largely taken over in the enthusiast
and hobbyist market. However, film speeds are not simply of interest to
those working with more traditional technologies. Film speeds differentiate
between the light-sensitive qualities of different types of film stock; these
qualities are available to the photographer using digital technology.
FIG 7.20
Images created using
different ISO setting allow for
the capture of action in different
situations. a: Slow action allows for
greater detail to be captured. b: A high
ISO setting allows for much higher
camera speeds, though this results in
image “noise.” c: Low light conditions
calls for higher ISO settings that allow
you to use the shutter speeds required
to capture the action, even if it is a
slow action. d: This low ISO setting
allowed for capture of detail even
with a shallow depth of field.
The rate at which photographic film material reacts to light is known as the
film's
speed
. The faster the film reacts to light, the higher the speed rating
of the film. Digital cameras do not use film stock, but the sensors of digital
cameras react to light in the same way film does. Unlike film stock, which
has a predetermined sensitivity, the sensitivity of the CCD sensor can be
(a)
(b)
(c)
(d)
