Your camera has two physical mechanisms for controlling light. It has a shutter, and an aperture. A shutter is simply a mechanism that allows you to control how long the image sensor will be exposed to light.As the shutter is open longer, more light will strike the image sensor and your image get brighter and brighter. Shutter not only control light , shutter will affect how any motion in a scene will appear in your image. Motion in a photo image can be "frozen" or appear as blurred.