| A
| B | C |
D | E | F | G
| H | I | J
| K | L | M
| N | O | P
| Q | R | S
| T | U | V
| W | X | Y
| Z
A
3x, 5x, 10x - Denotes
the focal length ratio of a zoom lens - this is an optical, not digital zoom.
See also "Digital Zoom" below.
AA - In the digicam world this
refers to the most common power source, the AA-size battery. See also "NiCd"
and "NiMH" and check here: NiMH Batteries/Chargers.
AA Filter - Most digital SLR
cameras employ a Low Pass Filter (LPF) or Anti-Aliasing (AA) filter in front of
the imager to help eliminate color aliasing (moire) problems.
AC Power - Running your digicam
off the wall outlet power rather than by battery power. Usually means purchasing
optional AC power adapter.
Add-On Lens - Some lenses have
filter threads on the front edge that allow you to mount an auxiliary wide angle
or telephoto lens in addition to the standard lens.
AE - Auto Exposure, a system
for automatically setting the proper exposure according to the existing light
conditions. There are three types of AE systems:
- Programmed where the camera picks the best shutter speed
and aperture automatically.
- Aperture Priority, the user chooses an aperture value and
the shutter speed is automatically determined by lighting conditions.
- Shutter Priority, the user chooses a shutter speed and the
aperture is automatically determined by lighting conditions.
AE Lock - The ability to hold the current exposure settings and
allow you to point the camera elsewhere before capturing the image. This is usually
accomplished by half-pressing the shutter button and keeping it at that position
until you're ready to capture the image.
AF - Auto Focus. A system that
automatically focuses the camera lens.
Aliasing - An effect caused
by sampling an image (or signal) at too low a rate. It makes rapid change (high
texture) areas of an image appear as a slow change in the sample image. Once aliasing
occurs, there is no way to accurately reproduce the original image from the sampled
image.
Algorithm - A mathematical
routine that solves a problem or equation. In imaging, the term is usually used
to describe the set of routines that make up a compression or color management
program.
A/D Converter - A device that
converts analog information (a photograph or video frame) into a series of numbers
that a computer can store and manipulate. All digicams use an A/D converter, the
higher the bit rate the better the output. Modern hi-res digicams employ a 12-bit
or 14-bit A/D to increase the dynamic range (range of light from highlight to
shadow).
Anti-aliasing - The process
of reducing stair-stepping by smoothing edges where individual pixels are visible.
Aperture - The lens opening
formed by the iris diaphragm inside the lens.
Aperture Priority AE - Exposure
is calculated based on the aperture value chosen by the photographer. This allows
for depth of field (DOF: Range of focus) control - large aperture = shallow DOF
and a small aperture = deep DOF.
Archive - A collection of data
in long-term storage.
Artifact(ing) - Misinterpreted
information from a JPEG or compressed image. Color faults or line faults that
visibly impact the image negatively.
Aspect Ratio - The ratio of
horizontal to vertical dimensions of an image. (35mm slide frame is 3:2, TV 4:3,
HDTV 16:9, 4X5 film 5:4)
Aspherical Lens - A lens whose
edges have been flattened so that it is not a perfect sphere, produces a superior
image.
Automatic Exposure - The camera
automatically adjusts the aperture or shutter speed or both for the proper exposure.
Autofocus - The camera lens
focuses automatically, usually when the shutter release is half-pressed.
AVI - Movie clip in Windows'
AVI format. See "Movie clip"
AWB - Automatic White Balance.
A system for automatically setting the white balance in today's digital cameras.
See also "White Balance"
A | B
| C | D | E
| F | G |
H | I | J | K
| L | M | N
| O | P | Q
| R | S | T
| U | V | W
| X | Y | Z |
