What is Shutter Speed in photography?

What is Shutter Speed?

Shutter speed refers to the length of time the shutter is open and therefore the sensor or film is exposed to light. The longer the shutter is open, the more light will hit the sensor, and vice versa.

How does it work?

Shutter speed is measured in seconds and it's usually depicted as a reciprocal, so 1/60th of a second will generally be marked as 60 on the camera. Typical shutter speeds below, but most modern cameras are capable of faster and slower speeds:

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

Each of these speeds is referred to as a stop, and each stop will let through twice the light of the previous one. So 1/500th of a second will let double the amount of light through than 1/1000th of a second. This is important because shutter speeds work in conjunction with aperture values to provide a good exposure, as described in the exposure post.

Many cameras come with 2 additional settings for shutter speed that have a very specific purpose:

• B (or Bulb) - which keeps the shutter open for as long as the shutter release is pressed
• T (or Timed) - which opens the shutter when the shutter release is pressed once and closes it when it's pressed again

Why is it important?

As with aperture, shutter speed has a big influence on what the final photograph will look like.

A slow shutter speed allows you to:

1. Create blur in the image to suggest movement. For example, by placing the camera on a tripod and selecting a slow shutter speed, the background will be sharp and the objects that are moving will be blurred. Other use is panning (or following a moving subject) while the shutter is open. This usually creates a blurred background with the followed object sharper.
2. Shoot in low light conditions. If there isn't enough light available, putting the camera on a tripod and using slower shutter speeds will allow enough light through for a good exposure.
3. Shoot with a smaller aperture for more depth of field.

A fast shutter speed allows you to:

1. Freeze moving subjects. For example, sports photographs where a moment is frozen in time use fast shutter speeds.
2. Shoot in very bright conditions. Sometimes there is just too much light in the environment.
3. Shoot with a larger aperture for shallower depth of field.