Exposure

Exposure – allowing light to hit the camera sensor to record an image – is measured in what’s commonly referred to as ‘stops’, with each stop representing either double or half the level of exposure of the adjacent stop. Increase the exposure by one stop, and the camera sensor receives twice the level of exposure. Decrease it by one stop, and the exposure level is halved.Exposure is the amount of light per unit area (the image plane illuminance times the exposure time) reaching a photographic film or electronic image sensor, as determined by shutter speed, lens aperture and scene luminance. Exposure is measured in lux seconds, and can be computed from exposure value (EV) and scene luminance in a specified region.