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 at a given ISO, using a single number [..]

Abbreviated EV, always with a plus or minus number attached, it indicates the degree of exposure change with exposure compensation or backlight compensation--for example, +1.5 EV, –0.5 EV.

A number determined by the brightness of the subject and the sensitivity selected for the recording medium, it is larger for bright subjects and smaller for dark ones. When the amount of light doubles [..]

A number representing all available combinations of aperture and shutter speed resulting in the same exposure (with scene brightness remaining the same). The EV +/- setting on the camera is used to make the image more or less exposed in automatic modes (ones that the camera calculates the Aperture and shutter speed). It is common in ambient light u [..]