Light meter:A microchip that
senses and measures the intensity of
light striking it. (See Chapter 5.)10 PART 1 GETTING TO KNOW DIGITAL CAMERAS
Shutter button:A switch
that, when pressed, triggers
an exposure by locking
autofocus and autoexposure
and opening the shutter.
(See Chapter 5, “How Digital
Exposure Sifts, Measures,
and Slices Light.”)Menu controls:Knobs or
buttons that allow you to
make selections from a
software menu displayed
on the LCD screen.Infrared light source:Theautofocus
mechanism uses infrared rays that have
bounced off the subject to determine the
distance from the camera to the subject.
(See Chapter 3, “How Lenses Work.”)LCD read-out window:Usually in
combination with the digital control, this
window tells you information such as the reso-
lution, number of shots left, and battery power.When light first strikes the lens, it is incoherent
light, or light that travels in all directions indis-
criminately. The light might be no brighter than a
shadow in a cave, or it might be the glare of the
Sahara at noon. But that light is no more an
image than mere noise is music. It’s the role,
mainly, of two parts of a camera—the focus and
exposure systems—to mold light into an image
that captures and freezes one momentary slice of
time and place. In the digital world, new tools let
us refine the photograph even further, but the
photography still starts with the tools that get the
pictures into the camera in the first place.Creating the Image
White Balance button:Adjusts
the camera so that, when the camera
photographs a white object, it dis-
plays a “true” white regardless of
how artificial lighting might intro-
duce off-white hues. (See Chapter 5.)