A light meter is a device used to measure the amount of light. In photography, a light meter (more correctly, an exposure meter) is used to determine the proper exposure for a photograph. The meter will include either a digital or analogue calculator that displays the correct shutter speed and f-number for optimum exposure, given a certain lighting situation and film speed. Similarly, exposure meters are also used in cinematography and scenic design to determine the optimum light level for a scene.