Glossary of Terms

E-6 – the chemistry used to process most slide films (excluding Kodachrome).

Effective pixels – the number of pixels used to make up an image. A typical sensor uses some pixels to measure background electron flow as a way of reducing noise. Total pixels therefore typically exceed effective pixels.

Electromagnetic spectrum – the range of frequencies of electromagnetic radiation. It extends from radio waves to gamma rays and incorporates the spectrum of visible radiation (light) to which the human eye is sensitive.

Electronic viewfinder – typically a small LCD monitor used to display an image captured by a sensor in a digital camera.

Emulsion – light sensitive silver halide crystals, combined with other chemicals, laid on a film base or other backing material.

Exposure – process or period during which light is allowed to fall on a sensor or sensitized material to produce a latent image. Exposure is usually controlled by opening a shutter for a specific period of time.

Exposure compensation – generally, the process of manually intervening in, or offsetting by small increments, an exposure determination made by an automatic exposure setting system.

Exposure latitude – the range of exposure variation that a film, or electronic sensor, can tolerate without loss of image quality.

Extension tube – a hollow tube inserted between a camera body and a lens to increase magnification. It is useful for close-up work.