Shutters function like an eye lid. They control how long light enters a camera. There are two main types of shutters, focal plane and leaf.
Shutter speeds are fractions of a second. Fast shutter speeds such as 250, 500, or 1000 are good for action shots.
Slow Shutter Speeds
Slow shutter speeds such as 1,2, or 4 are good for low light pictures and pictures where water looks soft and like cotton.