shutter speed

shutter speed (countable and uncountable, plural shutter speeds)

1. (photography) The duration of time for which the shutter of a camera remains open when exposing photographic film or other photosensitive material to light for the purpose of recording an image.
   • 1993 November 21, Charles Hagen, “CAMERA: For Film Exposure, Timing Is the Key”, in New York Times, retrieved 4 Apr. 2009:

     Shutter speeds are usually measured in seconds or fractions of a second, and are typically arranged in a sequence that includes 1, 1/2, 1/4, 1/8, 1/15, 1/30, 1/60, 1/125, 1/250 and 1/500.