DSLR Tutorials: Shutter Speed
The camera's shutter gives controls to the amount of light entering the camera. Think of it like the shutters on the house window. When the shutters are closed, they block out light. When the shutters are fully open, all the light enters the room. The shutter button on DSLRs opens the shutter for a predetermined amount of time, specified by the shutter speed.
Shutter speeds are measured in fractions of a second.
example: 1/125, 1/250, 1/500, 1/1000, etc.
Some cameras may display just the denominator. So, if the camera just displays 500 it really means 1/500 of a second.
When shooting scenes that require extremely long exposures, such as the taillights of traffic at night, your shutter speeds will likely be 1 second or longer. Long exposures can be made with shutter speeds such as 1, 10, or even 30 seconds. Tip: When using a shutter speed of 1/60 sec., or slower, it's best to use a tripod to mount you camera, because if the camera moves even slightly, you are likely to have some blurring.
Controlling the shutter speed allows you to take control over "time" and how it is viewed in your photograph. You can capture a moment in time using a higher shutter speed or you can slow down time by using a slower shutter speed.