What is a shutter?

A shutter is a device that is used to block or regulate the amount of light that enters a camera or a room. It is typically found on cameras and other imaging equipment, such as telescopes and microscopes, and is used to control the duration of the exposure to light.
In a camera, the shutter is usually a mechanical component that consists of a pair of curved metal blades that are connected to a spring. When the shutter is activated, the blades open and close quickly to allow a burst of light to reach the film or digital sensor. The length of time that the shutter is open, known as the «shutter speed,» is measured in fractions of a second and can be adjusted to control the amount of light that enters the camera.
In addition to regulating the amount of light that enters a camera, the shutter can also be used to control the way that moving objects are captured in an image. By using a fast shutter speed, it is possible to freeze the motion of a moving object and capture a clear, sharp image. On the other hand, a slow shutter speed can be used to create a blurred effect for moving objects, which can be used to convey a sense of motion or action in an image.