What is Shutter Speed?
In photography photography the shutter speed is the unit of measurement which determines how long shutter remains open as the picture is taken with your cameras sensor.
The slower the shutter speed, the longer the exposure time. The shutter speed and aperture work together to control the total amount of light reaching your camera sensor.
Shutter speeds are expressed in seconds or fractions of a second. For example 2, 1, 1/2, 1/4, 1/8, 1/15, 1/30, 1/60, 1/125, 1/250, 1/500, 1/1000, 1/2000, 1/4000, 1/8000. Each speed increment halves the amount of light reaching your camera sensor.
A fast shutter speed is typically used for sports or nature photography when you need to capture fast moving subjects. A longer shutter speed it used for low light and astrophotography when you need a longer exposure to allow enough light into your camera’s sensor.
Through animation in this video Apalapse explains shutter speed.