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Digital Camera Dictionary
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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"
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.
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"
B&W - Term used to mean black and white
Back Lit - The subject is heavily lit from behind which generally causes it to
be underexposed unless you use critical spot metering.
Backlight - The illumination for a color LCD display. Early color LCD used
high voltage fluorescent lamps, newer LCDs now use white LEDs which are much more
energy efficient.
Banding - An artifact of color gradation in computer imaging, when graduated
colors break into larger blocks of a single color, reducing the "smooth" look of a
proper gradation.
Barrel Distortion - A common geometric lens distortion causing an acquired image
to pucker toward the center.
Bit - The smallest unit of memory; a contraction from 'binary' and
'digit'. Binary digits are 0 and 1, also known as ons and offs.
Bit Depth - This refers to 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 - The method of storing information that maps an image pixel,
bit by bit. There are many bitmapped file formats, .bmp, .pcx, .pict,
tiff, .tif, .gif, and so on. Most image files are bit mapped. This type of
file gives you the 'jaggies', when examined closely you can see the line of
pixels that create the edges.
Bleed - Printing term referring to an image or linked area that extends
to the edge of the printed piece.
Blooming - A visual effect caused by overexposing a CCD to too much light,
This "digital overexposure" can cause distortions of the subject and/or color.
Blue Tooth - The new wireless standard for connecting cameras, PDAs, laptops,
computers and cell phones. Uses very high frequency radio waves. Blue Tooth devices
when in-range (less than 30 feet) of each other easily establish a connection.
BMP - BitMapped graphic file format popular with Windows computers.
This is an uncompressed file format like TIFF.
Bracketing - see Exposure Bracketing
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. The purpose of a buffer
is to act as a temporary holding area for data that will allow the CPU to manipulate
data before transferring it to a device.
Also see DRAM Buffer
Burst Mode - The ability to rapidly capture images as long as the shutter
button is held down.
Byte - An ensemble of eight bits of memory in a computer.
Calibration - The act of adjusting the color of one device relative to another,
such as a monitor to a printer, or a scanner to a film recorder. Or, it may be the
process of adjusting the color of one device to some established standard.
Card Reader - A device that you insert flash memory cards into to
transfer the data to the computer. Much faster than the serial port! See
also "PCMCIA" and "PC Card"
CCD - Charged Coupled Device, a light sensitive chip used for image
gathering. In their normal condition these are grey scale devices.
To create color a color pattern is laid down on the sensor pixels, using
a RGBG color mask (Red, Green, Blue, and Green) The extra Green is used to
create contrast in the image. The CCD Pixels gather the color from the light
and pass it to the shift register for storage. CCDs are analog sensors, the
digitizing happens when the electrons are passed through the A to D
converter. The A to D converter converts the analog signal to a digital
file or signal. See also "CMOS" below
CD - CompactDisc - read only storage media capable of holding 650MB of
digital data.
- CDR - CompactDisc Recordable - a CD that you can write to once that can not
be erased but can be read many times, holds 650~700MB of digital data.
- CDRW - CompactDisc ReWriteable - the newest kind of CD-R that can be erased
and re-used many times, holds about 450MB of data.
Center-Weighted - A term used to describe an auto exposure system that uses
the center portion of the image to adjust the overall exposure value.
See also "Spot Metering" and "Matrix metering"
CF - see CompactFlash
Channel - One piece of information stored with an image. True color images,
for instance, have three channels-red, green and blue.
Chroma - The color of an image element (pixel). Chroma is made up of
saturation + hue values, but separate from the luminance value.
Chromatic Aberration - Also known as the "purple fringe effect." It is common
in two Megapixel and higher resolution digital cameras (especially those with long
telephoto zoom lenses) when a dark area is surrounded by
a highlight. Along the edge between dark and light you will see a line or two of purple
or violet colored pixels that shouldn't be there.
CIFF - Camera Image File Format, an agreed method of digicam image storage
used by many camera makers.
CMOS - Complementary Metal Oxide Semiconductor - Another imaging system used
by digicams. It is not as popular as CCD but the future promises us
even better digicams based on CMOS sensors due to the lower amount of
power consumption versus the typical CCD device.
CMS - Color Management System. A software program (or a software and hardware
combination) designed to ensure color matching and calibration between video or
computer monitors and any form of hard copy output.
CMYK - Cyan, Magenta, Yellow, blacK; These are the printer colors
used to create color prints. Most color printers, Ink-Jet, Laser,
Dye-Sublimation and Thermal printers use these as their printer
colors. (This is one of the color management problems for computers.
Converting RGB files to CMYK files cause's color shifts.) When used by a
printer the CMYK is also known as a reflective color since it is
printed on paper, or reflective films.
Codec - 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 captured in the image
match the original scene.
Color Cast - An unwanted tint of one color in an image caused by a
disproportionate amount of cyan, magenta, and yellow. This can occur due to
an input or output device.
Color Copier - Color printing device using electrostatic and CMYK Pigments.
Color Correction - The process of correcting or enhancing the color of an image.
Color Depth - Digital images can approximate color realism, but how they do
so is referred to as color depth, pixel-depth, or bit depth.
Modern computer displays use 24-bit True Color. It's called
this because it displays 16 million colors, about the same
number as the human eye can discern.
Color Space - Digital cameras use known color profiles to generate their
images. The most common is sRGB or AdobeRGB and this information along with the
camera and exposure data is stored in Exif header of the JPEG file. This color
space information ensures that graphic programs and printers have a reference
to the color profile the camera used at the time of exposure.
see ICC Profile for more information.
CompactFlash - The most common type of digicam flash memory
storage. It is removable, small and available in sizes from 4MB up to
1GB.
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.
COM port - Your computer has serial communication ports which support the
RS-232 standard of communication. This is the most common
interface used to transfer data from a digicam to the computer.
Compression - A digital photograph creates an image file that is huge, a
low-resolution 640x480 image has 307,200 pixels. If each pixel
uses 24 bits (3 bytes) for true color, a single image takes up
about a megabyte of storage space. To make image files smaller
almost every digital camera uses some form of compression. See
the "JPG" entry below.
Continuous Autofocus - The autofocus system is full-time and works even before
the shutter release is pressed.
Continuous Tone - An image where brightness appears consistent and
uninterrupted. Each pixel in a continuous tone image file uses at least one byte
each for its red, green, and blue values. This permits 256 density levels per color
or more than 16 million mixture colors.
Contrast - A measure of rate of change of brightness in an image.
CRW - The raw CCD file format used by Canon digicams. Abbreviated from
CanonRaW.
DC - Direct Current. Battery power as in 9v DC battery
DC - Also used as an abbreviation for DigiCam (digital camera)
Decompression - The process by which the full data content of a compressed
file is restored.
Densitometer - A tool used to measure the amount of light that is reflected
or transmitted by an object.
Depth of Field - depth of field (DOF) Range of sharp focus. Controlled by the
aperture opening of the lens. A large aperture yields shallow DOF. Smaller apertures
yield deeper DOF.
Diffusion Dithering - A method of dithering that randomly distributes pixels
instead of using a set pattern.
Digital Film - Term used to describe solid state flash memory cards.
Digital Zoom - A digital magnification of the center 50% of an image.
Digital zooms by nature generate less than sharp images
because the new "zoomed" image has been interpolated.
Digitization - The process of converting analog information into digital
format for use by a computer.
Dithering - A method for simulating many colors or shades of gray with only a
few. A limited number of same-colored pixels located close together is seen as a new
color.
DOF - Abbreviation for Depth of Field (see above).
Download - Transfer image data from the camera to the computer using a
cable attached to either the serial port (slow) or USB port (faster.)
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. 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. Mostly
used by commercial photo finishers or those Kodak kiosks you find in the mall.
DRAM - Dynamic Random Access Memory. A type of memory that is volatile -
it is lost when the power is turned off.
DRAM Buffer - All digicams have a certain amount of fixed memory in them to
facilitate image processing before the finished picture is stored to the flash
memory card. Cameras that have a burst mode have much larger DRAM buffers, often
32MB or larger. This also makes them more expensive.
DVD - "Digital Versatile Disc"
DVD is DVD-Video recorded on a DVD-R or DVD-RW disc, which contains superior quality
video (MPEG-2) and audio. Typically, a DVD can hold more than one hour of video.
DVD Video Parameter Settings
Frame Size: 720x480 (NTSC) or 720x576 (PAL)
Frame Rate: 29.97 frames/second (NTSC) or 25 frames/second (PAL)
Video Data Rate: 4~8 Mbps CBR or VBR (Constant/Variable Bit Rate)
Audio Settings: Stereo, 48 kHz and 192~384 kbps MPEG audio
Dye Sub - Dye Sublimation is a printing process where the color dyes are
thermally transferred to the printing media. Dye sub printers use the CMYK (cyan,
magenta, yellow, black) color format and have either three ribbons (cyan, magenta and
yellow) or high-end printers have four CMY plus a blacK. The paper is run in and out
of the printer four times, once for each color and then a fourth time when a
protective overcoat is applied. Dye sub is continuous tone printing, it prints tiny
square dots each of which is denser in the center and lighter on the edges. These
dots can be varied from almost no dot at all to an almost completely solid dot. The
dyes are transparent so different colored dots can be printed on top of each other to
form any one of 16-million colors. This is known as the
subtractive color
process. Dye sub prints rival conventional photographs in both their color gamut
and longevity with water and UV resistant qualities.
For the sake of accuracy we must state that most printers today that claim to be
dye sub type printers are actually dye diffusion. The complete technical name for
this process is Dye Diffusion Thermal or "D2T" printing. To achieve true sublimation
printing requires a laser to vaporize the dye material. The common 4x6" dye sub or
the bigger ones that do up to 8x10" prints like the
Olympus P-400
or
Kodak Pro 8500
heat the dye material with a thermal printhead and use pressure rollers to push the
ribbon into contact with the paper and then diffusion occurs.
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.
EPP - Enhanced Parallel Port - the newer hi-speed, bidirectional printer
port on modern computers. Some older digicams and scanners use the EPP port
to transfer data.
ERI-JPEG -
Extended
Range Imaging Technology, a new file format used in Kodak professional digital cameras.
This proprietary technology offers an innovative image file format similar to a JPEG, but
with the dynamic range and color gamut information of raw DCR camera files. Extended
Range Imaging Technology files allow you to easily open, edit, and print JPEG files
within your JPEG workflow. Your JPEG files are captured directly in the camera. With ERI,
you'll have the extensive editing, color balance, and color compensation capabilities of
RAW digital negatives for applying to your JPEG files.
E-TTL - Canon's Evaluative-TTL exposure system that uses a brief pre-flash
before the main flash to calculate the exposure index.
EV - Exposure Value, a very complex thing but in the digicam world it usually
means the ability to override the auto exposure system to lighten or
darken an image.
EVF - Electronic ViewFinder, a small color LCD with a magnified lens that
functions as an eye level viewfinder. Usually found on video camcorders but they have
been showing up on super-zoom digicams where optical viewfinders are impractical.
(Canon Pro90, Fuji 2800Z, Olympus C-2100, Nikon Coolpix 5700).
EXIF - EXIF (Exchangeable Image File format) refers to the embedded camera and exposure information that a
digital camera puts in the header of the JPG files it creates. Many graphic programs
(Photoshop, ThumbsPlus, Qimage Pro, CameraAid) can read and display this information.
Exif Print - Exif Print (Exif 2.2) is a new worldwide printer independent standard. Under Exif
2.2, the digital still camera can record data tags for specific camera settings and
functions such as whether the flash was on or off, if the camera was in
landscape, portrait or night scene mode, etc. Referencing some or all of this
information, an Exif Print compatible application can process digital camera images
intelligently based on specific camera settings and the shooting environment.
See the
Exif Print-CIPA web page for more info.
Exposure - The amount of light that reaches the image sensor and is controlled
by a combination of the lens aperture and shutter speed.
Exposure Bracketing - the camera automatically takes a series of 3 or 5
pictures and slightly varies the EV for each frame. This insures that at least one
of the pictures will be as close to perfectly exposed as possible.
Exposure Compensation - Lighten or darken the image by overriding the exposure
system. Also known as EV Compensation.
f-stop - A numerical designation that indicates the size of the aperture.
It is inversely proportional as a smaller number like F2.8 is a large opening and
a large number like F16 is a relatively small opening.
FDD - Floppy disk drive, the most common being a 1.44MB 3-1/2" drive like
those used in today's PC computers.
File - A collection of information, such as text, data, or images saved on a
disk or hard drive.
File Format - A type of program or data file. Some common image file formats
include TIFF, JPEG, and BMP.
Fill Flash - Using the flash to lighten shadow areas or just to provide more
overall illumination in situations where you normally wouldn't use the flash. Outdoors
in bright light you get very stark shadows underneath of people's noses, chins and etc.
Toggle the flash setting to "forced on" or "fill" and the flash will now fire on every
shot. It also gives your human subjects that special little sparkle in their eyes.
FireWire - Also known as "iLink" and officially designated as the IEEE 1394
protocol. A high-speed data interface now
being used on digital camcorders and digital still cameras. For lots
of Firewire info go to
Adaptec's Firewire web page
Firmware - An often-used micro program or instruction set stored in
ROM. Usually refers to the ROM-based software that controls a unit. Firmware
is found in all computer based products from Cameras to Digital Peripherals.
Fixed Aperture - Normally when a zoom lens goes from wide angle to telephoto the
aperture changes. If the camera has an option to fix the aperture value then it
remains constant regardless of focal length.
Fixed Focal Length - A term that describes a non-zoom lens, it is fixed at a
given focal length and is not variable.
Fixed Focus - A lens that is preset to a given focus distance, it has no
autofocus mechanism, set to give the camera the maximum depth of field
Flash - A built-in flash supplies auxiliary light to supplement natural or
available lighting conditions often resulting in better color, better exposure, and
improved picture sharpness.
Flash Memory - This is the "film" for digital cameras, it can be erased
and reused many times. It is non volatile memory, data is preserved even when it is
not under power. They are several major types used in digital cameras;
CompactFlash, SmartMedia and Memory Stick.
Flash Memory Reader - See Card Readers
Flashpath - A device that allows a SmartMedia card to be inserted into a
regular floppy diskette drive and its data transferred to the computer. There is
also now a Flashpath device for Memory Stick cards too.
Flat Bed Scanner - An optical scanner in which the original image remains
stationary while the sensors (usually a CCD linear array) passes over or under it.
The scanned material is held flat and scanned using a reflective process.
Floppy Disk Adapter - A device that resembles a 3-1/2" floppy diskette
and allows a SmartMedia cards or Sony Memory Stick modules to be read in a standard
1.44MB floppy disk drive.
Focal Length - A lens' angle of view, most commonly indicated as wide angle,
normal or telephoto. Usually compared to a 35mm camera's
lenses as in "the camera has a wide angle lens equivalent to a
38mm lens on a 35mm camera." See also "Zoom Lens"
Focus Assist - Some cameras employ a visible or invisible (infrared) lamp
to illuminate the subject so the autofocus can work in low light or total darkness.
Focus Lock - Pre-focusing the camera and then moving it to re-compose the image
before capturing it. Accomplished by half-pressing the shutter button and keeping it
held at that position while moving the camera to another point before pressing it all
the way to capture the image.
FPX - FlashPiX - Trade name for a new multi-resolution image file format
jointly developed and introduced in June 1996 by Kodak, HP, Microsoft and Live Picture.
Frame - One of the still pictures that make up a video.
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.
Full Bleed - Printing term used when an image or inked area extends to the
edge of all four sides of the printed piece.
Gamma - A measure of the amount of contrast found in an image according to the
properties of a gradation curve. High contrast has high gamma and low contrast low gamma.
Gamma Correction - In reference to displaying an image accurately on a
computer screen, Gamma correction controls the overall brightness of an image.
Images which are not properly corrected can look either bleached out, or too dark.
For more info on gamma,
go here
Gamut - The range of colors that are available in an image or output process.
It is generally used in describing the capabilities of a printer to reproduce colors
faithfully and vibrantly - i.e. "The xxxxx printer has a wide color gamut."
GIF - A graphic file format used mainly for Web graphic or small animated files.
Not good for photos as it only contains a maximum of 256 colors.
Gigabyte (GB) - A measure of computer memory or disk space consisting of about one
thousand million bytes (a thousand megabytes). The actual value is 1,073,741,824
bytes (1024 megabytes).
Gradation - A smooth transition between black and white, one color and another,
color and no color.
Gray Level - The brightness of a pixel. The value associated with a pixel
representing it's lightness from black to white. Usually defined as a value from 0 to
255, with 0 being black and 255 being white.
Gray Scale - A term used to describe an image containing shades of gray rather
than color. Most commonly referred to as a black and white photo.
Guide Number - The output power rating of a electronic flash unit.
HAD CCD - Sony's latest CCD imager, HAD = Hole Accumulation Diode
Halftone Image - An image reproduced through a special screen made up of dots
of various sizes to simulate shades of gray in a photograph. Typically used for
newspaper or magazine reproduction of images but it is also how today's inkjet
printers work. Halftoning or dithering are the methods used to produce a smooth
gradation of color versus distinct bands of color or moirè patterns.
HD - Hard drive (aka HDD), the internal, large-capacity data storage unit
in today's PC computers.
HDTV - High Definition Television. New video "standard" that will resolve
1,125 lines in the United States instead of the traditional 525 lines of the NTSC
standard.
Histogram - A bar graph analysis tool that can be used to identify contrast
and dynamic range of an image. Histograms are found in the more advanced digicams
and software programs (graphic editors) used to manipulate digital images. The
histogram shows a scale of 0 - 255 (left to right) with 0 being black and 255
being white.
Hot Shoe - A flash connector generally found on the top of the camera that lets you
attach a flash unit and trigger it in sync with the shutter.
Hue - A term used to describe the entire range of colors of the spectrum; hue
is the component that determines just what color you are using. In gradients, when you
use a color model in which hue is a component, you can create rainbow effects.
ICC Profile - The International Color Consortium, a group that sets standard
guidelines for color management in the imaging world. Click here to read their
FAQs about color management
and ICC profiles and the like. Most printers, monitors and scanners as well as
digital cameras, usually come with a driver disc for Windows and Mac systems that
includes ICC profiles for the particular device. Color profiles simply let one piece
of hardware or software "know" how another device or image created its colors and
how they should be interpreted or reproduced.
IEEE-1284 - This is the high-speed bidirectional parallel port
specification, used by printers and devices like card readers.
IEEE-1394 - Better known as "FireWire" - it's the new input/output bus
used by digital video devices & PCs. For lots
of Firewire info go to
Adaptec's Firewire web page
iLink - Sony's term for IEE-1394 FireWire data port found on their camcorders.
Image Processing - Capturing and manipulating images in order to enhance or extract information.
Image Resolution - The number of pixels per unit length of image. For example, pixels per inch, pixels per millimeter, or pixels wide.
Image Sensor - A traditional camera exposes a piece of light-sensitive film,
digital cameras use an electronic image sensor to gather the
image data. See "CCD" and "CMOS" as well as "Interlaced" and
"Progressive Scan"
Image Stabilization - An optical or digital system for removing or reducing
camera movement in telephoto zoom lenses. Usually found only on extremely long focal
length lenses such as the 10X lens on the Sony FD91, FD95, FD97 and CD1000 or the
Canon Pro90 or Olympus C-2100UZ, E-100RS.
InfoLITHIUM - Sony's "smart" lithium rechargeable battery pack. It has a
chip inside that tells the camera how long (in minutes) it will last at the current
discharge rate.
Inkjet - A type of printer that sprays dots of ink onto paper to create the
image. Modern inkjet printers now have resolutions of up to 2880dpi and create true
photo-quality prints.
Interlaced - Term used to describe an image sensor that gathers its data by
first processing the odd lines and then the even lines. See
also "Progressive Scan" for the other (preferred) method.
Interpolated - Software programs can enlarge image resolution beyond
the actual resolution by adding extra pixels using complex mathematic
calculations. See "Resolution" below
IR - InfraRed (aka IrDA) uses an invisible (to humans) beam of light to either
wirelessly control a device or as a method of transferring data from camera to
computer (or printer) without cables. Some cameras also employ infrared in the
auto focusing system.
ISO - The speed or specific light-sensitivity of a camera is rated by ISO
numbers such as 100, 400, etc. The higher the number, the more
sensitive it is to light. As with film, the higher speeds usually induce more
electronic noise so the image gets grainier. ISO is the abbreviation for
International Standards Organization. (In the good old days it was known
as the "ASA film speed.")
"Jaggies" - Slang term for the stair-stepped appearance of a curved or
angled line in digital imaging. The smaller the pixels, and the
greater their number the less apparent the "jaggies". Also
known as pixelization.
JFIF - A specific type of the JPG file format. Also known as EXIF
JPEG - Joint Photographic Experts Group - The name of the committee
that designed the standard image compression algorithm. JPEG is designed for
compressing either full-color or grey-scale digital images of "natural", real-world
scenes. It does not work so well on non-realistic images, such as cartoons or line
drawings. JPEG does not handle compression of black-and-white (1 bit-per-pixel) images
or moving pictures. See "JPG" below.
JPEG2000 - The new JPEG compression standard that will be used in digital
cameras and software starting in 2002 (maybe?). It will feature higher compression
but with less image quality loss.
JPG - The most common type of compressed image file format used in digicams.
It is a "lossy" type of storage because even in its highest quality mode there is
compression used to minimize its size.
KB - Can be used to mean either a keyboard for a computer or more commonly
"KB" means a kilobyte of data.
Landscape Mode - Holding the camera in its normal horizontal orientation to
capture the image. See Portrait Mode.
LCD - Liquid Crystal Display. Two types: (1) a TFT high-resolution
color display device like a tiny TV set. (2) A monochrome (B&W) information display
using black alphanumeric characters on a gray/green background.
LED - Light Emitting Diode. All those wonderful little red, green and yellow
indicator lights used on cameras, power supplies and most electronic devices.
Lithium - Some digicams are packaged with a lithium
rechargeable battery pack. Lithium batteries are lighter but more costly than NiMH
or NiCd type of rechargeable cells. Lithium cells can be recharged regardless of their
state of discharge.
Lossless - Storing the image in a non-compressed format, see TIFF.
Mac - Refers to the Macintosh type of computers
Macro - The ability of a lens to focus very close (less than 8") for taking
pictures of small objects at a 1:1 ratio.
mAh - A rating used in the consumption of power of an electronic device such
as an LCD or the storage capability of a device like an NiMH or Nicad
rechargeable battery (i.e. 1600mAh cell). It stands for milliAmperehour.
Matrix metering - In most digicams there is a matrix
metering option which uses 256 areas of the frame to calculate
the best overall exposure value.
see also: "Spot metering" and "Center-weighted"
MB - MegaByte, memory term meaning 1024 KiloBytes. Used to denote the size
of a flash memory card such as 4MB, 8MB etc. (MB [megabyte] is often confused
with Mb [megabit], there's 8 bits in a byte so 256Mb = 32MB.)
MD - MiniDisc - Digital recording media like a small floppy disc. This is
common for audio data and has been used on several digicams sold in
Japan and Europe but not in the U.S. yet.
Megapixel - CCD resolution of one million pixels. Digicams are commonly
rated by Megapixels. You multiply the horizontal resolution by the vertical
resolution to get the total pixel count:
1280 x 960 pixels = 1 Megapixel
1600 x 1200 pixels = 2 Megapixels
2048 x 1536 pixels = 3 Megapixels
Memory Stick - A flash memory card standard from Sony. They
resemble a stick of gum and currently (09/02) come in sizes from 4MB up to 128MB.
Metering - Used to calculate the exposure from the existing light
conditions. See: "Matrix Metering," "Spot metering" and "Center-weighted"
Microdrive - IBM's miniature hard disk drive for digital cameras and
PDA devices. Packaged in a CompactFlash Type II housing and available in
170MB, 340MB, 512MB and 1GB capacities. See my
Microdrive
user review
miniCD - The small diameter (3-inch) CD discs. miniCD-R and miniCD-R/W discs
are used in the Sony CD200, CD250, CD300, CD400 and CD1000 digicams. Their
maximum capacity is ~165MB
mm - millimeter, measurement to denote the focal length of a lens (i.e. 50mm)
MMC - MultiMedia Card, a flash memory card used in some digicams and MP3 players.
It is identical in size and shape to the Secure Digital (SD) flash cards.
MMP - Steve's new anochronym for MultiMegaPixel meaning two or
more mega(million)pixels in resolution.
Moirè - A visible pattern that occurs when one or more halftone screens are
misregistered in a color image. Often produces a colored checkerboard or rainbow pattern.
MOV - Apple QuickTime MOVie file format. See "Movie clip"
Movie clip - A sequence of motion captured in AVI, MOV or MPEG
format. Some digital cameras can capture short movie
sequences, some can also record the sound.
Motion JPEG - A video sequence composed of a sequence of JPEG compressed
images. Abbreviated to MPEG (see MEG below).
MP - Abbreviation for MegaPixel, i.e. 1.5MP or 1.5MPixel
MPEG - Motion JPEG movie file. See "Movie clip"
The digital video compression standard agreed upon by the Motion Picture Expert
Group, from the motion picture-computer industry.
MPEG-EX - Motion JPEG movie file created by Sony cameras. This was the
first motion video recording sequence mode that was limited in length only by
the amount of available storage space.
MPEG-HQX - Motion JPEG movie file created by new (2002 model) Sony cameras
that incorporates the MPEG-HQ (high quality, full-screen) and the unlimited
recording capability of MPEG-EX in 320x240 resolution.
Multi Spot Focusing - The autofocus systems uses SEVERAL different portions
of the image to determine the proper focus.
Multi Zone Focusing - Many digital cameras now offer multi
zone focusing. The camera will automatically determine which zone (center, left,
right, upper, lower) to use to perform the auto focusing. You no longer have to
make sure that your subject is dead-center to be properly focused.
NEF - Raw image data file format used by the Nikon D1, D1x, D1h, D100 pro SLR
and Coolpix 5700 digicams. NEF means Nikon Electronic Format.
NiCd - Nickel Cadmium (aka Nicad), a type of rechargeable battery. Nicad was
the original type of rechargeable battery and has been pretty much
replaced by the NiMH type.
NiMH - Nickel-Metal Hydride, a type of rechargeable battery. NiMH is the
more modern type of rechargeable battery and has been touted as having
no memory effect as is common with Nicad type batteries when they are
charged before they have been fully discharged. NiMH may also be
called NiHy by some folks.
Noise - Pixels in your digital image that were misinterpreted. Usually occurs
when you shoot a long exposure (beyond 1/2-second) or when you use the higher ISO
values from 400 or above. It appears as random groups of red, green or blue pixels.
NTSC - Term used to describe the 60 field video output (television) standard
used in the U.S. and Japan.
See also "PAL" and "Video Out"
OEM - Original Equipment Manufacturer. Means that the piece of equipment is
made by one company but labeled for and sold by another company.
OLED - Organic Light Emitting Diode - Newly developed display technology that
could replace LCD. OLED does not require a backlight like LCD displays and therefore
is more energy efficient which is important to battery-operated portable devices.
It also offers increased contrast and a better viewing angle which means it
can be more easily viewed in bright (sunlight) conditions.
Optical Viewfinder - An eye level viewfinder that is used to compose the photograph.
Optical Zoom - Means that the camera has a real multi-focal length lens, this
is not the same as a "Digital Zoom" which magnifies the center portion
of the picture.
ORF - Olympus RAW format. The unprocessed image format created by Olympus
E10, E20 and C-5050 Zoom cameras.
Orientation Sensor - A special sensor in some cameras that "knows" when your turn
the camera in portrait orientation to take a vertical shot and "tells" the camera to
display it that way later when viewed on the TV screen during playback.
Overexposure - An image that appears too light. All the
highlights and colors are totally lost and usually unrecoverable
even by software.
PAL - The 50 field video format used primarily in Europe and
other places outside of the U.S. and Japan. See also "NTSC" and "Video Out"
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 more colors the larger the data and the more processing time required
to display your images. If the system uses 24-bit color, then over 16.7 million
colors are included in the palette.
Panorama - Capturing a series of images to create a picture wider than what you
could capture in a single image. Requires special "stitching" software to combine and
blend the images into one finished image.
Parallax - An effect seen in closeup photography where the viewfinder
does not see the same as the lens due to the offset of the viewfinder and the lens.
This is a non-issue if using the LCD as a viewfinder or if your camera is a SLR type.
PC - In camera terms it denotes a type of flash synch connector, popular on
most film cameras.
PC - In computer terms it means a Personal Computer as in IBM-PC
PC Card - Refers to a credit card-sized device which can be a flash
memory card, a network card, a modem or even a hard drive.
Comes in two flavors: Type I/II which is a single slot height and
Type III which requires a double-height card slot.
PCMCIA - The card slots found on laptop computers to use PC Cards.
There are PCMCIA adapters for CompactFlash, SmartMedia, Secure Digital,
MultiMediaCard and Memory Stick flash cards.
Photo CD - Kodak's professional service
where they process your film and then scan the images using a very expensive
drum scanner and output these images to a CD. You get several different
sized resolution images of each of your film pictures, from small to very
large. PhotoCD is multi-session which means more than one roll of pictures may
be put on each PhotoCD disc.
PICT - A graphics file format used primarily on Macintosh computers. PICT files
can contain both object-oriented and bit-mapped graphics. There are two types: PICT I
and PICT II. PICT II is the current standard and supports color up to 24-bit.
PictureCD - Kodak's amateur service of putting your camera images (1,534-by-1,024)
onto a CD disc. 35mm or APS camera pictures can be put on the PictureCD discs
for about $8.95 - $10.95 on top of regular processing fees. One roll per PictureCD.
PIM - PRINT Image Matching - Epson's new standard of embedded color and printing
information for digital cameras. Many of the camera manufacturers have joined with Epson
and now embed the PIM information in the Exif header of the JPEG images created. Epson
just announced at PMA 2002 the new Exif 2.2 standard incorporating their PIM info.
See the Epson
PIM web site.
Pixel - The individual imaging element of a CCD or the individual output
point of a display device. This is what is meant by the figures
640x480, 800x600, 1024x768, 1280x960 and etc when dealing with the
resolution of a particular digicam. Higher numbers are always
better!!
Pixelization - The stair-stepped appearance of a curved or angled line in
digital imaging. The smaller the pixels, and the greater their
number, the less apparent the "pixelization" of the image.
Also known as the "jaggies".
Plug-n-Play - An automated installation process used in MS Windows to connect
peripherals to a computer. When new devices are plugged into the computer the computer
recognizes the device and prompts the user to choose setup options and finish
installation.
Polarizer - A photographic filter for eliminating glare and reflections.
Just like your polarized sunglasses get rid of annoying glare, the polarizer filter
does the same for your digicam. However - there are 2 types, linear and circular.
Linear is for film only, it screws up most auto focus systems on digicams. Therefore
be sure you use a circular polarizer filter. It can also be used to darken skies.
Want to learn more -
click here
PNG - An image file format. PNG stands for Portable Network Graphics.
It is a compressed file format similar to JPG.
Point and Shoot - A term used for a simple, easy to use camera with a
minimum of user controls. Generally the user turns the camera on, aims it at the
subject and presses the shutter button. The camera does everything automatically.
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.
Pre-Flash - Some digicams use a low-power flash before the main flash to set
the exposure and white balance. This does not allow the use of a normal photo slave
strobe as it will be triggered by the pre-flash.
Programmed AE - the camera picks the best shutter speed and aperture
automatically, also called "Automatic" or "Point-n-Shoot" mode.
Progressive Scan - Term used to describe an image sensor that gathers its
data and processes each scan line one after another in
sequence. See also "Interlaced" for the other method.
Prosumer - Refers to more expensive semi-professional digicams costing
$1,500 and up. The average digicam is made for the
consumer market and costs well under $1,000.
QuickTime - A motion video standard created by Apple. They have an entire
QuickTime web site to explain it.
QuickTime video sequences can contain an audio track and are stored as .MOV files.
QVGA - Refers to a Quarter-VGA resolution (320 x 240) motion video sequences.
RAM - Random Access Memory . The most common type of computer memory; where the
CPU stores 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 closeups for this very reason.
RAW - RAW files basically hand the raw unprocessed data - at 12 bits per channel - from the camera’s imaging chip to your
computer. Lossless compression is applied to reduce filesize slightly without compromising any quality.
Red-Eye - An effect caused by an electronic flash reflecting off of the human
eye and making it look red. Compact cameras with the flash located close to the lens
suffer the worst from this problem. Pro photographers use a bracket to hold an
external flash unit above and off to the side of the lens to eliminate red-eye.
Red-Eye Reduction Mode - A special flash mode whereby a pre-flash or a series of
low-powered flashes are emitted before the main flash goes off to expose the picture.
This causes the pupil in the human eye to close and helps eliminate red-eye.
Render - The final step of an image transformation or three-dimensional scene
through which a new image is refreshed on the screen.
Resize - Usually means to take a large image and downsize it to a smaller one.
Most graphic viewing and editing programs offer a Resize option for this purpose.
Resolution - The quality of any digital image, whether printed or displayed
on a screen, depends in part on its resolution—the number of
pixels used to create the image. More and smaller pixels adds
detail and sharpens edges.
- Optical Resolution is an absolute number that the camera's
image sensor can physically record.
Interpolated Resolution adds pixels to the image using complex
software algorithms to determine what color they should be.
It is important to note that interpolation doesn't add any
new information to the image - it just makes it bigger!
Camera makers often specify the resolution as: QVGA (320 x 240), VGA (640 x 480),
SVGA (800 x 600), XGA (1024 x 768) or UXGA (1600 x 1200)
RF - Range Finder - a type of camera viewfinder that uses one lens to frame
your subject and another lens to capture the image. See "SLR" for the
other type.
RGB - Means Red, Green and Blue - the primary colors from which all other
colors are derived. The additive reproduction process mixes various amounts
of red, green and blue to produce other colors. Combining one of these
additive colors primary colors with another produces the additive secondary
colors cyan, magenta and yellow. Combining all three produces white.
RS-232 - Standard type of serial data interconnection available on most
PC type computers. It is the slowest way to transfer image data from a camera.
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 - An optical device that converts images - such as photographs - into
digital form so they can be stored and manipulated on computers. Different methods of
illumination transmit light through red, green and blue filters and digitize the image
into a stream of pixels.
SCSI - A high-speed input/output bus used mainly in Macintosh
computers but also popular in many high-end PCs. Abbreviation for Small Computer
Systems Interface.
SD - Secure Digital card, a flash memory card used in digicams and MP3 players.
It is identical in size and shape to the MultiMedia Card (MMC) flash cards. The
difference being that SD cards were designed to hold protected (copyrighted)
data like songs. Not all cameras that use SD cards can use MMC cards so be sure
to read your owner manual before buying additional cards.
Secure Digital - Secure Digital. See "SD" above.
Sepia - The (brown) mono-toned images from the "good ole days" now often found
as a special image effect on some digicams.
Serial Port - Same as "RS-232" above.
Shutter - The physical device that opens and closes to let light from the scene
strike the image sensor. Digicams use both electronic and mechanical 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 Priority AE - the user chooses a shutter speed and the aperture is
automatically determined by lighting conditions. Shutter speed priority is used
to control motion capture. A fast shutter speed stops fast action, a slow shutter
speed blurs a fast moving subject.
Slow Sync - A special mode in digicams that opens the shutter for a longer than
normal period and fires the flash just before it closes. Used for illuminating a
foreground subject yet allowing a darker background to also be rendered. Good for
night time shots of buildings with people in the foreground.
SLR - Single Lens Reflex - Means the camera has a viewfinder that sees through
the lens (TTL) by way of a 45°-angled mirror that flips up when the shutter fires and
allows the light to strike the image sensor (or film).
SmartMedia - (aka SSFDC), a flash memory card that consists of a thin piece
of plastic with laminated memory on the surface and uses a gold contact
strip to connect to the camera. It's really not very "smart" as it has no
onboard controller on the card, the controller is in the camera. SmartMedia
cards are available from 4MB up to 128MB in size.
Smoothing - Averaging pixels with their neighbors. It reduces contrast
and simulates an out-of-focus image.
Spot Metering - The camera's auto exposure system is focused on a very small
area in the center of the viewfinder to critically adjust the overall
exposure value ONLY for that area.
see also: "Center-weighted" and "Matrix metering"
SSFDC - Solid State Floppy Disc Card - See "SmartMedia" above
Subtractive Color - Photographs and objects of nature create color by
subtracting or absorbing certain wavelengths of color while reflecting other
wavelengths back to the viewer. This is called subtractive color. Example - The
common apple, it is seen as "red" by the human eye or a digital camera. The apple
really has no color (light energy of its own), it merely reflects certain wavelengths
of white light that cause us to see red and absorbs most other wavelengths.
Color paintings, color photography and all color printing processes use the
subtractive process to reproduce color. In these cases, the reflective substrate is
canvas (paintings) or paper (photographs, prints), which is usually white.
SVCD - "Super Video Compact Disc"
A CD-ROM disc that contains high quality video and audio. Typically, a SVCD can hold about
35~45 minutes (650MB) of video and stereo-quality audio (depends on the data rate used for
encoding). The video and audio are stored in MPEG-2 format, much like a DVD. SVCD video
has better quality than VHS video.
SVCD Video Parameter Settings
Frame Size: 480x480 (NTSC) or 480x576 (PAL)
Frame Rate: 29.97frames/second (NTSC) or 25 frames/second (PAL)
Video Data Rate: Variable bit rate up to 2600 kbps
Audio Settings: 32~384 kbps MPEG-1 Layer 2 audio bit rate
SVGA - Refers to an image resolution size of 1024 x 768 pixels.
Telephoto - The focal length that gives you the narrowest angle of coverage,
good for bringing distant objects closer.
TFT - Refers to the type of hi-res color LCD screen used in digicams.
TFT = Thin Film Transistor.
Thermal Dye Sublimation - please see Dye Sub
Thumbnail - A small, low-resolution version of a larger image file that is used
for quick identification or speedy editing choices.
TIFF - Tagged Image File Format - An uncompressed image file format that is
lossless and produces no artifacts as is common with other image
formats such as JPG.
Time-Lapse - Capturing a series of images at preset intervals.
True Color - Color that has a depth of 24-bits per pixel and a total of
16.7 million colors.
TTL - Through the Lens, used when talking about either an autofocus or
auto exposure system that works through the camera's lens. It's also
(incorrectly) used to mean SLR, see "SLR" above.
Type I, II, III - Denotes various PC ATA 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.
See also "PCMCIA" and "PC Card"
TWAIN - 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. The word TWAIN is the abbreviation of
"Technology Without An Industry Name."
Underexposure - A picture that appears too dark because insufficient light
was delivered to the imaging system. Opposite of
overexposure.
Unsharp Masking - A process by which the apparent detail of an image is
increased; generally accomplished by the input scanner or through computer
manipulation.
USB - Universal Serial Bus - the data I/O port on most digicams and found
on modern PC and Mac computers. Faster than the serial port. Up to 12MB/s
USB 2.0 - The newest USB standard, close in throughput speed to FireWire now.
Up to 400MB/s.
UXGA - Refers to an image resolution size of 1600 x 1200 pixels.
VCD - "Video Compact Disc"
A CD-ROM disc that contains video and audio. Typically, a VCD can hold about 74 minutes
(650MB) of video and stereo-quality audio. The video and audio are stored in MPEG-1
format and follow certain standards (White Book). VCD video quality is roughly the same
as VHS video.
VCD Video Parameters Settings
Frame Size: 352x240 (NTSC) or 352x288 (PAL)
Frame Rate: 29.97 frames/second (NTSC) or 25 frames/second (PAL)
Video Data Rate: 1152 kbps
Audio Settings: Stereo, 44.1kHz and 224kbps audio bit rate
VGA - Refers to an image resolution size of 640 x 480 pixels.
Video Out - Means the digicam has the ability to output its images on
television screens and monitors using either NTSC or PAL format.
Viewfinder - The eye level device you look through to compose the image.
Vignetting - A term that describes the darkening of the outer edges of the
image area due to the use of a filter or add-on lens. Most noticeable when the
zoom lens is in full wideangle.
White Balance - Refers to adjusting the relative brightness of the red,
green and blue components so that the brightest object in
the image appears white. See also "AWB"
wide angle - The focal length that gives you the widest angle of coverage.
X3 Image Sensor - Foveon's new image sensor for digital cameras that captures
red, green and blue data at every pixel. Read the
X3 press release for full details.
xD-Picture Card - A new flash memory card standard that was co-developed by
Fujifilm and Olympus in mid-2002. Rumored to be replacing SmartMedia which has
stalled at 128MB. xD is scheduled to go as large as 8GB in a form factor the size
of a postage stamp.
XGA - Refers to an image resolution size of 1024 x 768 pixels.
ZLR - Zoom Lens Reflex, a term coined by Olympus to describe their fixed mount
lens SLR type cameras. An SLR camera has interchangeable lenses, a ZLR has a
non-removeable zoom lens.
Zoom Lens - A variable focal length lens. The most common on digicams
has a 3:1 ratio (i.e. 35-105mm). See "3x" and "Focal Length"
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