Nikon manual David Busch’s Nikon D7000 Guide to Digital SLR Photography

492 David Busch’s Nikon D7000 Guide to Digital SLR Photography

compression Reducing the size of a file by encoding using fewer bits of information to represent the original. Some compression schemes, such as JPEG, operate by dis- carding some image information, while others have options that preserve all the detail in the original, discarding only redundant data.

Continuous-servo autofocus An automatic focusing setting (AF-C) in which the cam- era constantly refocuses the image as you frame the picture. This setting is often the best choice for moving subjects. See also Single-servo autofocus.

contrast The range between the lightest and darkest tones in an image. A high-con- trast image is one in which the shades fall at the extremes of the range between white and black. In a low-contrast image, the tones are closer together.

Creative Lighting System (CLS) Nikon’s electronic flash system used to coordinate exposure, camera information, and timing between a camera’s built-in flash (if present) and external flash units, which can be linked through direct electrical connections or wirelessly. Some external flash units can act as a “master” to command other external units.

dedicated flash An electronic flash unit, such as the Nikon SB-700 Speedlight, designed to work with the automatic exposure features of a specific camera.

depth-of-fieldA distance range in a photograph in which all included portions of an image are at least acceptably sharp.

diaphragm An adjustable component, similar to the iris in the human eye, which can open and close to provide specific-sized lens openings, or f/stops, and thus control the amount of light reaching the sensor or film.

diffuse lighting Soft, low-contrast lighting.

digital processing chip A solid-state device found in digital cameras that’s in charge of applying the image algorithms to the raw picture data prior to storage on the mem- ory card.

diopter A value used to represent the magnification power of a lens, calculated as the reciprocal of a lens’s focal length (in meters). Diopters are most often used to represent the optical correction used in a viewfinder to adjust for limitations of the photographer’s eyesight, and to describe the magnification of a close-up lens attachment.

equivalent focal length A digital camera’s focal length translated into the correspon- ding values for a 35mm film camera. This value can be calculated for lenses used with the Nikon D7000 by multiplying by 1.5.

exchangeable image file format (Exif) Developed to standardize the exchange of image data between hardware devices and software. A variation on JPEG, Exif is used by most digital cameras, and includes information such as the date and time a photo was taken, the camera settings, resolution, amount of compression, and other data.