Dictionary of Computer and Internet Terms: EV (exposure value)
EV (exposure value)
in photography, a number that measures the effect of f-ratio and shutter speed together, as exposure adjustments. For example, an exposure of 1/250 second at f/8 is equivalent to 1/125 second at f/11; each of these is EV 14. Higher EV numbers correspond to shorter exposures or exposures at smaller (higher-numbered) f-stops. Adding 1 to the EV is equivalent to cutting the exposure in half. Thus 1/250 second at f/11 is EV 15.
Cameras often have "EV +/-" adjustments to deliberately increase or decrease the exposure. Here+1 means to expose more than the meter indicates, and -1 means to expose less than the meter indicates.
