| A/D
Converter |
(Analog to Digital)
A device that converts analog information (a photograph or video frame) into a series of
numbers that a computer can store and manipulate. |
| Angle
of View |
The amount of a scene that can be
recorded by a particular lens. This is determined by the focal
length of the lens. |
| Anti-aliasing |
The process of reducing
stair-stepping by smoothing edges where individual pixels are visible. |
| Aperture |
The maximum size of the hole
through which light enters the camera. |
| Artifact(ing) |
Distortions
or excess noise which are caused by the sensor, the optical system or image
processing (such as compression). |
| Aspect
Ratio |
The ratio between the width and
height of an image or image sensor. |
| Attachment |
A file sent along with an e-mail
message so that it can be viewed or saved by the recipient. |
| Automatic Exposure |
A feature where the camera
automatically adjusts the aperture or
shutter speed or both for the proper exposure. |
| Automatic
Flash |
A flash unit with a
light-sensitive cell that determines the length of the flash for proper exposure by
measuring the light reflected back from the subject. |
| Autofocus |
A system that automatically
focuses the camera lens. |
| Averaging |
See Matrix Metering. |
| AVI |
A video format used by Microsoft Windows®. |
| B&W |
Black and white. |
| Back
Lit |
The subject is heavily lit from
behind which generally causes it to be underexposed. |
| Banding |
An artifact of color gradation where graduated colors are reduced to larger
blocks of a single color. |
| Barreling |
A distortion which occurs with
wide-angle zoom, in which straight lines at the edges curve toward the center, giving the
image a barrel-like appearance. |
| Bit |
(BInary digiT)
The smallest unit of computer memory. |
| Bit
Depth |
The color or gray scale of an
individual pixel. A pixel with 8 bits per color gives a 24 bit image. (8 Bits x 3 colors is 24 bits.) 24 bit color
resolution is 16.7 million colors. |
| Bitmap |
A method of storing information
that maps an image pixel bit by bit. |
| Blooming |
A visual effect caused by overexposing a CCD
sensor, which can cause distortions of the subject and/or color. |
| BMP |
An uncompressed bitmapped file
format (BMP) used with Microsoft Windows. |
| Brightness |
The value of a pixel in an
electronic image, representing its lightness value from black to white. Usually defined as
brightness levels ranging in value from 0 (black) to 255 (white). |
| Buffer |
A temporary storage area usually
held in RAM and used as a temporary holding area for data. |
| Burst
Mode |
The ability to rapidly capture
images as long as the shutter button is held down. |
| Byte |
A group of 8 bits, the basic unit
of information for the computer. |
| Capture |
A term used in digital imaging
meaning " to photograph". The term is used to differentiate the method by which
the image is made. As the word "photograph" is closely associated to film
photography, "capturing" is applied to specify a digital sensor is used." |
| Card |
A sealed package containing
storage chips or other electronic devices for use in a card slot on a camera, printer,
computer, or other device. |
| Card
Reader |
A device, which allows your
computer to directly, read flash memory cards. See also PCMCIA and
PC
Card |
| CCD |
(Charge-coupled device)
An image sensor that reads the charges from the sensor's photosites one row at a time. |
| CDR |
(CompactDisc Recordable)
A recordable CD which can be written once, which holds 650~700 MB of digital data. |
| CDRW |
(CompactDisc ReWriteable)
A CD-R that can be erased and re-used many times, which holds about 450 MB of data. |
| Center
Weighted |
An autoexposure system that uses
the center portion of the image to adjust the overall exposure value. See
Spot Metering and
Matrix Metering |
| Chromatic Aberration |
A fringing effect around the
edges, which is caused by lens not focusing correctly. |
| CIFF |
(Camera Image File
Format) A method of digital camera image storage used by many camera makers. |
| CMOS |
(Complementary Metal
Oxide Semiconductor) An imaging system used by digital cameras. |
| Codec |
(Compression and
Decompression) Compresses information so that it can be sent across a network
faster, and decompresses information received via the network. |
| Color
Balance |
The accuracy with which the
colors in the image match those in the original scene. |
| Color
Correction |
The process of correcting or
enhancing the color of an image. |
| Color
Depth |
The number of bits assigned to
each pixel in the image and the number of colors that can be created from those bits. True
Color uses 24 bits per pixel to render 16 million colors. |
| Color-Filter Array |
The filter dyes placed directly
over each pixel on the chip surface (CCD,
CMOS). |
| CompactFlash |
(CF) The most
common type of digital camera flash memory storage. There are two types:
- CF Type I: the original 5mm high card
- CF Type II: cards and devices that are 9mm high. Type I devices are all solid state but
Type II devices include the new IBM Microdrive, a miniature, rotating hard drive. and
check here: Flash Memory Cards/Readers
- CF Type III: used in double-height slots only.
|
| COM
port |
A serial communication port which
support the RS-232 standard of communication. |
| Compression |
The process of reducing the size
of a file. Compression is either lossless or
lossy. |
| Continuous Autofocus |
An always-on autofocus system. |
| Contrast |
A measure of rate of change of
brightness in an image. |
Dark
Current
Dark Noise |
The charge accumulated by pixels
while not exposed to light. Normally, this charge is reduced or eliminated prior to
capturing a picture. |
| Decompression |
The process of restoring the
contents of a compressed file. |
| Depth
of Field |
The distance between the nearest
and farthest points that appear in acceptably sharp focus in a photograph. Depth of field
varies with lens aperture, focal length, and camera-to-subject distance. |
| Diaphragm |
The adjustable aperture of a
lens, which controls the amount of light passing into the camera and may be in front of,
within or behind the lens. |
| Digital
Zoom |
A digital magnification of the
center 50% of an image. Digital zooms increase the apparent image size by interpolation.
They do not increase the amount of image information. |
| Digitization |
The process of converting analog
information into digital format. |
| Diopter Correction |
An adjustment on the viewfinder
of a camera, allowing someone to adjust the viewfinder to their vision and removing the
need to wear their glasses when looking through it. Diopter adjustments cannot compensate
for all vision problems, only near and far sightedness can be compensated |
| Direct
Vision |
Cameras using an optical viewfinder. |
| Distortion |
A defect in an image caused by
the lens, such as barreling and
pincushioning. |
| Download |
Transfer data from a device to a
computer using a cable connection. |
| DPI |
(Dots Per Inch)
A measurement value used to describe either the resolution of a display screen or the
output resolution of a printer. |
| DPOF |
(Digital Print Order
Format) A format which allows you to embed printing information on your memory
card. Select the pictures to be printed and how many prints to make. Some photo printers
with card slots will use this info at print time. |
| DRAM |
(Dynamic Random Access
Memory) A type of memory that is lost when the power is turned off. |
| DRAM
Buffer |
Fixed memory used for image
processing before the image is stored. Cameras with a burst mode have much larger DRAM
buffers. This also makes them more expensive. |
Dye Sub
Thermal Dye Sublimation |
A printing process where the ink
is thermally transferred to printing media. Usually expensive but providing extremely high
quality. Thermal dye printers require special paper. |
| Dynamic
Range |
A measurement of the accuracy of
an image in color or gray level. More bits of dynamic range results in finer gradations
being preserved. |
f
numbers
f-stops |
A numerical designation (f/2, f
2.8, f3 etc.) indicating the size of the aperture. |
| Firewire |
see IEEE-1394 |
| Fixed
Focus |
A lens, which is preset to a
given focus, distance in order to provide the maximum depth of field. |
| Flash |
A flash supplies additional light
to compensate for low lighting, back-lighting and other lighting issues. |
| Flash Memory Card |
A card containing chips that
store images. |
| Flash
Memory Reader |
An accessory that attaches to
your computer by cable and allows your computer to read directly from a flash memory card. |
| Flash
RAM |
(Flash Random Access
Memory) Rewritable memory often used for temporarily storing information such as
digital pictures. |
| Flat
Bed Scanner |
An optical scanner in which the
original image remains stationary while the sensors pass over or under it. |
| Focal
Length |
The distance from the optical
center of the lens to the image sensor when the lens is focused on infinity, usually
expressed in millimeters. |
| Focus |
The process of bringing one plane
of the scene into sharp focus on the image sensor. |
| FPX |
(FlashPiX) An
image format that contains a number of resolutions, each of which is broken into tiles
that can be edited and displayed independently. |
| Frame |
One of the still pictures that
make up a video. |
| Frame
Grabber |
A device that lets you capture
individual frames out of a video camera or off a video tape. |
| Frame
Rate |
The number of frames that are
shown or sent each second. Live action relates to a frame rate of 30 frames per second. |
| Fringing |
A white fringe appearing on the
edges of objects in the image. |
| IEEE-1284 |
A high-speed bidirectional
parallel port specification used by printers and devices like card readers. |
| IEEE
1394 |
A port capable of transferring
large amounts of data. Currently the fastest available port. Commonly known as Firewire. |
| IFF |
(Interchange File Format)
the Amiga file format. |
| Image
Formats |
The method of compressing and
saving an image file. |
| Image Processing Time |
The time lag that occurs between
the shutter is pressed and the camera is ready to take another picture, which occurs while
the camera converts the image from an analog format to a digital format and stores the
data. |
| Image
Sensor |
A solid-state device containing a
photosite for each pixel in the image. Each photosite records the brightness of the light
that strikes it during an exposure. |
| Image Stabilization |
An optical or digital system for
removing or reducing camera movement. |
| Inkjet |
A type of printer that sprays
dots of ink onto paper to create the image. Modern inkjet printers can have resolutions of
up to 2880 dpi (dots per inch) and create true photo-quality prints. |
| Interlaced |
An image sensor that gathers its
data by first processing the odd lines and then the even lines. See also
Progressive Scan. |
| Interpolation |
Method used to increase the
resolution of an image map by adding pixels to an image based on the value of surrounding
pixels. This method can cause artifacting. |
| IR |
(InfraRed) A
method of transferring data from camera to a computer using a beam of invisible light,
requiring no cables. |
| IrDA |
A standard that allows data to be
transferred between devices using infrared light instead of cables. |
| ISO |
A number rating indicating the
relative sensitivity to light of an image sensor or photographic film. Faster film (higher
ISO) is more sensitive to light and requires less exposure than slower film. |
| Iris
Diaphragm |
A continuously adjustable lens
aperture consisting of interposed metal leaves. |
| Macro |
The ability of a lens to focus
very close (less than 8") for taking pictures of small objects at a 1:1 ratio. |
| Matrix
Array |
CCD's that can capture full-color
images instantaneously. |
| Matrix
Metering |
A metering method which uses the
entire image; however, it breaks the area down into smaller segments and uses the
individual readings to calculate the best possible exposure. Matrix-metering is the most
accurate of the metering systems. |
| MiniDisc |
(MD) Digital
recording media like a small floppy disc. |
| MB |
(Megabyte) 1024
kilobytes. |
| Megapixel |
(MP) Having a
resolution of one million pixels. A megapixel digital camera has an image resolution of
1280 x 960 pixels or greater. The most common digital cameras are rated at 1.3 megapixel,
2.11 megapixel and 3.34 megapixel. |
| Memory
Stick |
A flash memory storage device
developed by Sony that comes in sizes from 4 MB up to 128 MB. |
| Metering |
The process of calculating the
exposure from the existing light conditions. See: Matrix Metering,
Spot Metering and
Center Weighted |
| MMC |
(MultiMedia Card)
A flash memory card used in some digital cameras and MP3 players. |
| Moiré |
A visible pattern that occurs
when one or more halftone screens are misregistered in a color image. |
| MOV |
Apple QuickTime MOVie motion
video file format. |
| MPEG |
(Motion Pictures Expert
Group) A motion JPEG movie file. |
| Multi-megapixel |
An image or image sensor with
over two million pixels. |
| Multi Spot Focusing |
An autofocus system using several
different portions of the image to determine the proper focus. |
| Multiple Exposure |
An image made up of two or more
superimposed images. |
| Palette |
A thumbnail of all available
colors to a computer or devices. The palette allows the user to chose which colors are
available for the computer to display. The greater the number of colors, the larger the
data file becomes and more processing time is required to display your images. If the
system uses 24-bit color, then over 16.7 million colors are included in the palette. |
| Panorama |
A panorama shot is an extremely
wide-view image created by capturing a series of images. |
| Parallel
Port |
A port on the computer that is
faster than a serial port but slower than SCSI,
USB, or
IEEE
1394 ports. |
PC
Card
PCMCIA Card |
(Personal Computer Memory
Card International Association) A credit card-sized device which can be a flash
memory card, a network card, a modem or even a hard drive. |
| PCMCIA
Adapter |
A device that allows the use of
memory cards in a PCMCIA slot. The adapter accepts the smaller memory card and transfers
its connections to a standard PCMCIA connection |
| PCX |
A compressed, lossy file format
which supports RGB, indexed-color, grayscale, and bitmap color modes. |
| Photosite |
A small area on the surface of an
image sensor that captures the brightness for a single pixel in the image. There is one
photosite for every pixel in the image. |
| PICT |
A graphics file format used
primarily on Macintosh®
computers. |
| Pincushioning |
An effect which occurs with
telephoto zoom, in which straight lines at the edges curve in toward the far corners.
|
| Pixel |
(Picture Element)
An individual element of either a CCD sensor or a digital image. |
| Pixelization |
An effect seen when you enlarge a
digital image too much and the pixels become obvious. See also Jaggies. |
| PNG |
(Portable Network
Graphics) A compressed image file format similar to JPG. |
| Point
and Shoot |
A simple, easy to use camera with
a minimum of user controls and automatic control of most functions. |
| Port |
A connection point on the
computer that accepts a cable, allowing communication between the computer and another
device. |
| Portrait
mode |
Turning the camera to take a
vertically oriented photograph. |
| PPI |
(Pixels Per Inch)
A measurement to describe the size of a printed image. The higher the number, the more
detailed the print will be. |
| Preview
Screen |
A small LCD display screen on the
back of the camera used to compose or look at photographs. Also called Electronic Viewfinder. |
| Progressive
Scan |
An image sensor that gathers its
data and processes each scan line one after another in sequence. Compare to
Interlaced. |
| RAM |
(Random Access Memory)
The most common type of computer memory, which is used by the CPU to store software,
programs, and data currently being used. RAM is usually volatile memory, meaning that when
the computer is turned off, crashes, or loses power, the contents of the memory are lost.
A large amount of RAM usually offers faster manipulation or faster background processing. |
| Rangefinder |
The viewfinder on most cameras is
a separate viewing device that is independent of the lens. Often mounted above and to the
right or left of the lens. It exhibits a problem known as parallax when trying to frame
subjects closer than five feet from the camera so it is advisable to use the color LCD
when shooting close-ups for this very reason. |
| RAW |
(CCD raw format)
The uninterpolated data collected directly from the image sensor before processing. |
| Recycle
time |
The time it takes to process and
store a captured image. |
| Red-eye
and Red-eye Reduction |
Red-eye is an effect caused by an
electronic flash reflecting off of the human eye and making it look red. Red-eye reduction
mode fires a preliminary flash to close the iris of the eye before firing the main flash
to take the picture. |
| Refresh
rate |
The time it takes the camera to
capture the image after you press the shutter release. |
| Resolution |
Resolution is expressed as either
the number of pixels counted horizontally by the number of pixels counted vertically or by
the number of megapixels. It can be expressed as one of the following formats: QVGA (320 x
240), VGA (640 x 480), SVGA (800 x 600), XGA (1024 x 768) UXGA (1600 x 1200). |
| Resolution, Digital |
See Resolution, Interpolated. |
| Resolution, Interpolated |
A number based on adding pixels
to the image. Note: interpolation does not add any new information to the image. |
| Resolution, Optical |
An absolute number that the
camera's image sensor can physically record. |
| RGB |
(Red, Green and Blue)
The color system used in most digital cameras in which the image is separated by capturing
the red, green, and blue light separately and then are re-combined to create a full color
image. |
| Saturation |
The degree to which a color is
undiluted by white light. If a color is 100 percent saturated, it contains no white light.
If a color has no saturation, it is a shade of gray. |
| Scanner |
A device that uses light to read
printed information and converts it into the computer in a digital form for editing. |
| SCSI |
(Small Computer System
Interface) A high-speed input/output bus which is faster than serial and parallel
ports but slower (and harder to configure) than USB and Firewire ports. |
| SD Card |
(Secure Digital card)
A flash memory card identical in size and shape to the MultiMedia Card (MMC) flash cards. |
| Sensor |
An electronic device that
converts the light allowed in by the shutter to an electrical signal. |
| Sepia |
Describing the shades of brown
found in the pictures from very early in photography, the term is also used as a special
effect on some digital cameras, which converts the existing image into shades of brown. |
| Serial
Port |
Standard, but extremely slow,
connection port found on most computers. Also called RS-232. |
| Shutter |
The device in the camera that
opens and closes to let light from the scene strike the image sensor and expose the image.
The three primary types used in digital photography are digital
shutters, iris shutters and
focal
plane shutters. |
| Shutter
Lag |
The time between pressing the
shutter and actually capturing the image. This is due to the camera having to calculate
the exposure, set the white balance and focus the lens. |
| Shutter
Speed |
The length of time the shutter
opens to let light pass through the lens to the focal plane |
| SLR |
(Single-lens Reflex)
A camera that has one lens that is used for both composing the frame and capturing the
image to memory, as opposed to Range Finder. The same as TTL. |
| SmartMedia |
(SSFDC, Solid State
Floppy Disc Card) A popular form of flash memory card. |
| Smoothing |
An editing tool which averages
pixels with their neighbors to reduces contrast and simulate an out-of-focus image. |
| Spot
Metering |
A method of autoexposure based on
a meter reading of a small circle in the center of the viewfinder. |
| SVGA |
An image resolution of 800 x 600
pixels. |
| TIFF |
(Tagged Image File
Format) An lossless uncompressed image file format that produces no artifacts as
is common with other image formats such as JPG. |
| Telephoto |
A lens with a focal length that
gives you the narrowest angle of coverage, good for bringing distant objects closer. |
| TFT |
(Thin Film Transistor)
The type of hi-resolution color LCD
screen used in many digital photography cameras. |
| Thermal
Dye Sublimation |
see Dye
Sub. |
| Thermo
Autochrome Printer |
A printer technology that uses
specialized paper with three heat-sensitive pigment layers (cyan, magenta, and yellow) in
the paper. Each layer is sensitive to a different temperature. The printer selectively
heats areas of the paper with ultraviolet light, one color at a time, to activate and then
fix the pigments. |
| Thumbnail |
A small, low-resolution version
of a larger image file that is used for quick identification. |
| Time-Lapse |
Capturing a series of images at
preset intervals. |
| True
Color |
Color with a depth of 24-bits and
16.7 million colors. |
| TTL |
(Through The Lens)
An autofocus or autoexposure system that works through the camera's lens. |
| Type I,
II, III |
Denotes various PCMCIA or PC Card
storage devices (both flash memory and removable hard disk drives). Type I and II fit in
the single-height card slots, Type III only fit in the double-height slots. |
| TWAIN |
A protocol for exchanging
information between applications and devices such as scanners and digital cameras. TWAIN
makes it possible for digital cameras and software to "talk" with one another on
PCs. |
