LENS In photography, the optical instrument or arrangement of light-refracting elements in a group; the whole designed to collect and distribute rays of light in the formation of an image.

LENS, COMPOUND A lens composed of two or more separate elements with a common axis. (PIA)

LENS, MIRROR One employing reflecting elements in addition to light-transmitting elements; usually to obtain compactness in telephoto objectives. (PIA)

LENS ELEMENTS Individual simple lenses that are combined to form a compound lens. (PIA)

LIGHT, AMBIENT Surrounding light; the general room illumination or light level.

LIGHT, DIFFUSED Light that does not reach the subject in a single beam but is scattered by a medium, such as clouds, ground glass, spun glass, or thin fabric.

LIGHT, FILL-IN Secondary illumination directed to illuminate shadow areas and avoid excess contrast. Also known as fill light. (PIA)

LIGHT, INCIDENT The light that strikes an object, distinguished from the light reflected from or transmitted by the object. (PIA)

LIGHT, POLARIZED Light in which the electric vector of the wave vibrates in one plane, rather than all planes, as it does in ordinary (unpolarized) light. Light may become polarized by reflection or by passing through optical devices or sheets known as polarizers.

LIGHT BOX A device for viewing transparencies or negatives, providing diffuse illumination evenly dispersed over the viewing area.

LIGHT SENSITIVE Materials that undergo changes when exposed to light. The commonly used photographic light-sensitive materials are the silver halides used in films and papers, diazo dyes, and bichromated gelatin. (PIA)

LIGHTING, FLAT Illumination of a photographic subject often achieved by frontlighting or multiple sources with diffusers that minimizes contrasts and shadows. (PIA)

LIGHTING, FRONT Illumination on the subject coming from near the camera position. (PIA)

LIGHTING, INDIRECT Illumination by means of light reflected to the scene from shielded sources.

LIGHTING, LOW KEY A type of lighting which when applied to a scene results in a picture having gradations from middle gray to black, with comparatively limited areas of light gray and whites.

LINE COPY A document consisting essentially of two tones (such as black and white, black and tinted, and brown and buff) without intermediate tones.

LITER A unit of capacity in the metric system, equivalent to 1.056 quarts in United States customary liquid measurement. (PIA)

LOADING The insertion of photographic film, plates, or paper into holders, hangers, magazines, and so forth, before exposure or processing.

LONG SHOT In motion pictures, a scene filmed at a considerable distance from the camera to establish locale. Also applied to scenes which show full-length figures, as opposed to waist-length, head and shoulders, and so forth.

LOW-ANGLE (SHOT) Where camera is placed low and the scene is photographed at an upward angle.

LUX Lumen per square meter, a unit of illuminance.

MASK (l) An opaque sheet of thin material used to limit the area of a picture or to secure white margins on a photograph. (2) A supplementary negative or positive used for the purpose of contrast correction in black-and-white prints. (3) A supplementary positive either on a separate sheet or incorporated in an integral color tripack negative for the purpose of color correction. (PIA)

MATTE A relatively dull surface on photographic prints, having a very low level of specular reflection.

MATTE BOX A device attached to the front of a camera to hold mattes, filters, diffusing screens, and so forth, in front of the lens.

MEDIUM Any substances or space through which light can travel.

METER A unit of length measurement in the metric system approximately equal to 39.37 inches.

METOL-HYDROQUINONE (M-Q) Designating photographic developers that use a combination of metol and hydroquinone as the developing agent.