A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Easel - A darkroom device used to hold paper flat while exposing it to light from an enlarger. An easel creates a white border surrounding a print because its "arms" block light from striking the print paper's edges. The sliding arms can be adjusted vertically and horizontally in order to create prints of specific measurements - e.g. 4" X 6" or 5" X 7" and so on.

ED - "ED" refers to "Extra Low Dispersion" glass made by Nikon for some of its lenses. It ensures apochromatic-like performance, with high contrast and sharper images. An ED lens is one that has ED glass in one or more of its elements

EF - Abbreviation for "electronic flash."

EI - Abbreviation for Exposure Index.

Electromagnetic spectrum - The entire range of electromagnetic radiation - all of its wavelengths, including those of visible light.

Electronic flash  - Artificial light source produced by an electrical discharge travelling between two electrodes through a gas-filled tube. The light from electronic flash is approximately the same colour as daylight.

Element - A single lens that is a component of a compound lens.

Emulsion - The light-sensitive layer of a film. In black-and-white films the emulsion usually consists of very fine grains of silver halide suspended in gelatin, which blacken when exposed to light. The emulsion of color films contains molecules of dye in addition to the silver halide.

Emulsion side - The side of the film or photographic paper that has the emulsion coating on it. The emulsion side of film is recognized by being dull, whereas the emulsion side of paper is shiny.

Energy - The energy-stored in the flash-generator-that will be converted into light is reckoned and expressed in Ws (watt-seconds) or Joules. Energy is dependent on the capacitance of the capacitors and the voltage to which they are charged.

Enlargement - A photographic print that is larger than the film frame used in producing it. In popular use, however, most people think of an enlargement as being substantially larger than the image area of 35mm film - a print that is at least 5" X 7" or 8" X 10" in size. Also known as a "Blow-up."

Enlarger - An apparatus that makes enlarged prints by projecting and focusing an image from a negative or transparency onto light-sensitive paper, which must then be processed to reveal the final print.

Enlarger head - The part of an enlarger that contains the light source, the negative carrier and the lens. An enlarger head also houses a filter drawer or a built-in filtration system.

Enlarging easel (masking frame) - A board used with an enlarger for positioning printing paper and keeping it flat and still during exposure.

Existing light - The light that is naturally illuminating a scene without any additional light that has been added by the photographer. Ambient light and available light are two other terms that mean the same thing.

Exposure - The amount of light that passes through a lens (in either a camera or an enlarger) onto a light-sensitive material (film or photographic paper) to form an image. In the camera, too much light causes over-exposure - this makes negative film look too dark and reversal film look too light. Underexposure (too little light) has the reverse effect. In enlarging, overexposure makes a print from a negative too dark and a print from a slide too light Under­exposure has the reverse effect.

Exposure compensation - Deliberately changing the exposure settings recommended by a light meter in order to obtain proper exposure. (Sometimes an exposure meter or light meter is “tricked” into providing settings that will underexpose or overexpose an image, for example, when the subject is relatively small in a field of bright, white snow. In such a case, a light meter may provide exposure settings that would underexpose the subject, and the photographer needs to “compensate” for proper exposure.)

Exposure index or EI - A number that indicates a film's effective speed.

Exposure latitude - a measure of a specific film’s ability to be overexposed or underexposed and still produce an acceptable image. It is measured in a range of ƒ-stops. Most negative films (regardless of brand name) have an exposure latitude of five to seven stops, whereas most transparency (slide) films have less exposure latitude –– in the range of three to five ƒ-stops.

Exposure meter - An instrument for measuring the intensity of light so as to determine the shutter and aperture setting necessary to obtain correct exposure. Exposure meters may be built into the camera or be completely separate units.  Separate meters can sometimes measure the light falling on the subject (incident reading) as well as the light reflected by it (reflected read­ing):  built-in meters measure only reflected light. Both types of meter may be capable of measuring light from a particular part of the subject (spot meter­ing) as well as taking an overall reading.

Exposure setting - The aperture and shutter speed combination used to expose the film in a camera.

Exposure value - The Exposure Value (EV) system, which originated in Germany in the 1950s, was created to be a simple-to-use substitute for the shutter speed/aperture combination, using a single number instead of two.

Extension attachment - A camera accessory used in close-up photography to increase the distance between the lens and the film, thus allowing you to focus on very near objects. Extension tubes are metal tubes that can   be added in different combinations between the lens and the camera to give various increases in lens-to-film distance. Extension bellows are continuously variable between the longest and shortest extension, Bellows are considerably more cumbersome than tubes and must be used with a tripod.

Extension tubes - Tubes made from metal and, more frequently, plastic inserted between the lens and the camera, thereby making the lens to film distance greater. The result is increased magnification for close-up photography. They are sometimes also referred to as “extension rings”. They are frequently sold in sets of three different lengths, each of which can be used on its own or in combination with the others. When stacking more than one extension tube between the camera and lens, magnification can exceed life size. However, exposure time can be quite long as magnification increases since light must travel much further to strike the film.