In photography, shutter speed or exposure time is the length of time when the film or digital sensor inside the camera is exposed to light, also when a camera's shutter is open when taking a photograph. The amount of light that reaches the film or image sensor is proportional to the exposure time. 1/500th of a second will let half as much light in as 1/250th. The faster the shutter speed, the more the image will freeze in action. The slower the shutter speed is the more blurred the action is. This is how quickly the shutter opens and closes. The longer the shutter speed, the more light gets into the camera.