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Digital TermsAperture Priority: A mode in which a desired lens opening (f-stop) is manually selected and locked in; the camera then chooses an appropriate shutter speed for proper exposure. Used primarily to control depth of field (the range of sharpness) in front of or behind a subject or object. Artifacts: Unwanted effects in the image such as blotches (from over-compression), Christmas tree lights (multi-colored speckles from bright highlights), noise (granularity from underexposure) and other aberrations that sometimes afflict digicam images. Aspherical Lens: A lens designed to reproduce images better by having its edges flattened so that it is not a perfect sphere, hence: "a" (not) "spherical" (a sphere). Autofocus: The camera automatically focuses on a subject or object at which it is pointed. Buffer: An temporary electronic storage area where several already-exposed digicam images can wait in line to be processed. This speeds the interval between shots since each photo does not have to be processed before the next one can be taken. CCD: Charge-coupled device. The sensor array that makes up the imaging surface of the digicam. The more sensors a CCD has, the higher the image resolution will be. CMOS: Complimentary Metal Oxide Semiconductor. Used in some digicams instead of CCDs because they have low power requirements and are less expensive. CMYK: Cyan, Magenta, Yellow, and Black. The colors that are mixed to print pictures on paper. Most ink-jet and dye-sublimation printers use combinations of these colors to reproduce images. Color Temperature: A method of describing the qualities of warm (yellowish) or cool (bluish) light and measuring it in Degrees Kelvin (°K). Compact Flash: A matchbook-sized memory card used in many digital cameras today and presently capable of storing over 200MB of information. Compact Flash II: A new Compact Flash standard with increased capacity. Compression: Reducing digicam picture file sizes in the camera after theyre shot, usually according to Joint Photographic Experts Group (JPEG) specifications so more images can be stored on the memory card. The degree of compression can be user-specified on many models depending on the ultimate quality needed. dpi: Dots-per-inch. Printers lay down multiple dots of ink when printing to reproduce each pixel of the image. The higher the dpi rating of the printer, the better it can define each pixel. Also a measurement of a scanners resolution, although a more precise term would be spi (samples-per-inch). Depth Of Field: The range of sharpness in front of and behind the subject or object focused on. Digital Zoom: An electronic enlargement of part of the image making it appear to be closer and bigger, simulating an optical zoom lens at a telephoto setting. The image is actually cropped, resulting in loss of surrounding pixels and decreased resolution. In some digicams, interpolation is used to offset this loss. (see Interpolation). Downsampling: See "Interpolation" DPOF: Digital Print Order Feature. Allows pictures to be selected in the camera for future direct-from-memory-card printing on photo-finishing machines equipped with this feature. Dye Sublimation: A type of printing process in which a dye ribbon is heated by the print head creating a gas that hardens onto special paper. This creates soft-edged spots of color that melt into each other and give the appearance of a continuous tone photograph. EXIF: Exchangeable Image File. The JPEG compression mode used by most digicams. Exposure Compensation: A feature on most digicams that allows manual override of the cameras light meter to achieve better exposure under difficult lighting conditions. External Flash Synch: Allows connection to other flash units instead of (or in addition to) the digicams built-in flash. Very useful for experimenting with off-camera lighting effects and for use with studio strobes. Fixed Focus: The cameras focus is pre-set to a distance at which most subjects or objects will be in focus from near to far. Not as precise as autofocus. Flashpath: A floppy disk-sized shell into which a SmartMedia memory card is inserted so that images may be transferred directly to the computer through its floppy drive. Despite its convenience, it requires batteries and is slower than a PC (memory) card reader. Focal Length Equivalency: Since most users are familiar with 35mm camera lenses, digicam lens specs are frequently stated in those terms. For example, a digicam lens that zooms from 9.2mm to 28mm would be described as 36mm to 110mm (equiv). IBM MicroDrive: A high capacity (up to a Gigabyte) spinning storage device that can be used with digicams accepting Compact Flash II memory cards. Info-Lithium: A Lithium-Ion battery that indicates its remaining shooting time in minutes on the digicams LCD Monitor screen. Inkjet: A type of printing in which dots of ink are sprayed onto paper to create the image. Some inkjet printers can lay down 1440 dots of ink per inch, resulting in photo-quality prints (provided that the image has adequate resolution in pixels to begin with). Interpolation: The process of adding or subtracting pixels to an image (usually in an imaging program) to increase or reduce its size at a desired resolution. Also known as resampling or upsampling and downsampling. Interpolation changes the file size of the image. See also: "Resizing." ISO Equivalency: A measure of the digicams sensitivity to light using conventional film speeds as a yardstick. Most digicams have fixed ISO (International Standards Organization) equivalents but others can be set to sensitivities ranging from 80640 to achieve adequate exposure under different lighting conditions. Jaggies: The stair-stepping effect that can be seen in curves and diagonal lines when a pictures resolution is too low and individual pixels begin to show in the image. JPEG: Joint Photographic Experts Group (see "Compression"). LCD Monitor: The Liquid Crystal Display color screen on most digicams, usually 1.8 to 2.5 inches measured diagonally and used to check images after they are shot. The LCD monitor can also be used to frame pictures before they are taken and is usually more accurate than the optical viewfinder, though not as convenient to use. Lens Distortion: An abnormal rendering of lines in an image; most commonly they may appear to be bending inward (pincushion distortion) or outward (barrel distortion). Correctable by using a plug-in in an imaging program. Lithium-ion (LI-ion): A long-lasting rechargeable battery used in some digicams. Macro: The ability of a lens to focus just inches away from an object or subject so as to produce big close-ups, sometimes even larger-than-life size.
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©1998-2007 Arthur Bleich. All rights reserved. |
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