text: Camera Parts: Shutter - Steve's Digicams
  Shutter is one of the most important of the camera parts, as it allows the film or image sensor to be exposed to light for a particular period of time. The speed of the shutter can be set in many models so that you can control the amount of light entering the camera.
  The shutter mechanism operates in a cycle when you press the button. It first opens the door, then closes and then resets. Until the shutter resets you cannot operate it for another shot. This lag time is different in various models and if you are looking to take shots quickly you need to have a camera with the minimum lag time for its shutter.
  When you adjust the speed of your shutter you are regulating the camera's exposure to light. So if you want to take photos in less light you can set a lower shutter speed so that the shutter door remains open longer in order to allow more light in.
  There are basically two types of shutters; the leaf shutter and focal plane shutter. The leaf shutter is built inside the lens assembly, whereas the focal plane shutter is built in front of the film or image sensor.