After passing through the aperture of the lens, light reaches the shutter. Now you will take the decision about how much of light you want to permit into the camera. Shutter speed is adjusted depending on the light available and the object you are shooting. Normally, you need a small fraction of a second (1/250) to avoid motion blur. On the other hand, different shutter speeds set off different situations. For example, the sports photography requires really fast speed (1/4000) and the night photography needs slow speed (30 seconds).