What is shutter speed?

Shutter speed is the measurement (in fractions of a second) of time the camera's shutter allows light to strike the film or censor.

It is used to freeze action, create smooth waterfalls and eliminate camera shake from the operator.

The standard shutter speeds include the following:

1s 1/2s 1/4s 1/8s 1/15s 1/30s 1/60s 1/125s 1/250s 1/500s 1/1000s

<---- More exposure................................Less exposure ---->

You'll notice that each speed is half that of the preceding one. This is known as halving/doubling. Each speed either halves or doubles the amount of time light allowed to strike the film or sensor of the preceding speed. Modern cameras are able to use settings in-between the above to give greater exposure accuracy.

Most modern cameras can exceed 1/1000 of a second and can often reach 1/8000s. Most SLR cameras also have a B (Bulb) setting that allows you to hold the shutter open for as long as you need.

To obtain acceptably sharp results from a telephoto lens you should aim to use a shutter speed that is the reciprocal of the lens focal length. In other words, if you're using a 200mm lens then you should aim to use a shutter speed of no less than 1/250s of a second. If using a 500mm lens then 1/500s of a second should be used. This is a rule of thumb for hand-holding the camera. If you happen to have a tripod with you then you can use whatever shutter speed you like.

The longer the shutter is held open the more likely you are to blur the resulting image.