GLOSSARY GLOSSARY
low key A description of a photograph with a
dark overall tone.
manual exposure mode A camera mode where
the photographer determines the exposure by
setting both the shutter speed and the aperture.
metering modes The method the camera uses
to determine what light to use in the metering
process. See also center-weighted metering, scene
metering, and spot metering.
middle gray A tone that represents 18 percent
reflectance in visible light. All reflective light
meters, including the one in your camera, are cal-
ibrated to give an average reading of 18 percent
gray.
monopod A device with a single leg that helps
to steady a camera.
noise Extra unwanted pixels of random color in
places where only smooth color should be. Noise
is created when the signal from the image sensor
is amplified to get those high ISO settings. The
higher the ISO in a digital camera, the more
noise is created.
noise reduction Software or hardware used
to reduce unwanted noise in digital images. See
also noise.
normal lens A lens that produces images in a
perspective close to that of the human eye.
overexposure A condition that allows more
than the recommended amount of light to reach
the sensor, causing the image to appear too light
and with less detail in the highlights.
panning A method that involves moving the
camera in the same direction and speed that the
subject is moving, resulting in an image where
the subject is in acceptable focus while the back-
ground is blurred.JPEG Joint Photographic Experts Group. The
most commonly used and universally accepted
method for image file compression. JPEG is a
lossy form of compression, meaning that informa-
tion is lost during the compression when the file
is saved. JPEG files have a .jpeg or .jpg file exten-
sion. See also lossy.
Kelvin (K) A scale used to measure color tem-
perature. The Kelvin scale used in photography is
based on the color changes that occur when a
theoretical black body is heated to different tem-
peratures. High Kelvin has a blue cast while low
Kelvin has a red cast.
LCD Liquid Crystal Display. The type of dis-
play used on the back of most digital cameras
to preview photos and display menus and shoot-
ing data.
light meter A device used to measure the
amount of light in a scene. The readings from the
light meter can be used to determine what set-
tings produce a proper exposure. All digital cam-
eras have a built-in light meter that reads the
intensity of the light being reflected back from
whatever is in the scene.
lossless A form of computer file compression
applied when saving a file that allows the original
data to be reconstructed without losing any of the
information. This is useful when you want to
ensure that no changes are made to the informa-
tion. See also compression and TIFF.
lossy A form of computer file compression that
reduces the file size by removing data when the
image is saved. The file is not an exact match to
the original file, but close enough to be of use.
This form of compression suffers from generation
loss. Repeatedly compressing the same file results
in progressive data loss and image degradation.
See also compression and JPEG.