ED (Extra Low Dispersion) Glass

A glass developed and trademarked by Nikon Corporation, used in telephoto lenses to offer superior sharpness and color correction by minimizing chromatic aberration. These lenses are resistant to temperature changes, preventing focus shift problems in lenses that use calcium fluorite crystal elements. Fluorite cracks easily and is sensitive to temperature changes that can adversely affect focusing by altering the lens’ refractive index.

ED lens

A Nikkor lens having at least one ED element in its optical formula, improving sharpness.

Emulsion

The light sensitive, chemically active surface on photographic film and paper.

Enlargement

A photographic print made by "enlarging" an image from a piece of film.

EV

Exposure Value. A number representing equivalent shutter speeds and lens apertures combinations for the same exposure, given a scene brightness. At ISO 100, 0 represents (f/1.0 at 1 sec); 1 = (f/1.4 at 1 sec) or (f/1.0 at 1/2 sec); 2 = (f/2.0 at 1 sec) or (f/1.4 at 1/2 sec) or (f/1.0 at 1/4 sec) and so on. For a fixed aperture, as the EV increases 1, the shutter speed increases one step; for fixed shutters speeds, as the EV increases 1, aperture decreases one f/stop. Long exposures are for (or have) negative EV. A light meter sensitivity is usually defined as having the capacity to read an EV range for a given ISO speed.

EXIF

Exchangeable Image File: the file format used by most digital cameras. For example, when a typical camera is set to record a JPEG, it’s actually recording an EXIF file that uses JPEG compression to compress the photo data within the file.

Exposure

The amount of light that reaches a film frame or a digital sensor or the combination of f-stop (light intensity) and shutter speed (duration) that controls the amount of light reaching the film or sensor. Also used to describe an exposed piece of film.

Exposure Compensation

Deliberately changing the exposure settings recommended by a light meter in order to obtain a different exposure to better fit personal preferences, create special effects or meet special requirements.

Exposure Factor

A multiplier for the exposure increase required when the light reaching the film is decreased from either increasing the distance between the lens and the film (as with extension tubes and bellows) or when a filter is attached. Users with cameras with TTL meters need not to be concerned about correction for filters.

Extension Rings

Rings used to extend the distance between lens and film/sensor for macro or close-up work (One or several for various magnification ratios). Current Nikon extension rings are the PK11A (8mm), PK12A (14mm), PK13A (27.5mm). Sometimes also called Extension Tubes.

External Flash

A supplementary flash unit (speedlight) that connects to the camera via the hotshoe or a cable, or is triggered by the light from the camera’s internal built-in flash. For fun, creative effects and better lighting, usually with longer reach than a built-in unit.

Eyepiece Correction

Lens Attaches to the viewfinder eyepiece to correct for eyesight deficiencies. High-end cameras have a built-in diopter correction.

Eyepiece magnifier

An optical device that attaches to the eyepiece for increased magnification; useful for close-up or macro work and/or when manual focusing for fine detail is chosen.

Eyepiece shutter

A blind that blocks the eyepiece to prevent light to come into the viewfinder, altering correct measurements of the light meter when using the self-timer or at any time when the photographer is not there to block such light.