Shutter speed

Shutter speed is a photographic term for the time a camera's shutter is open. Light is allowed to reach the digital sensor's pixels (or film) for the duration of time the shutter is left open. Generally, the shutter speed is measured in a fraction of a second.

The faster the shutter open and closes the less the subject's reflected light can reach the sensor. If the subject is moving, the subject movements are for shorter distances for a faster shutter speed. Let's say your naked subject is running along the beach at 6 miles/hr. That is 8.8 feet/second. If your shutter was open for a full second (a very long time), the light reflected off her naked body from the moment the shutter open to the moment it closed would all reach the sensor. She would be blurred for that 8.8 feet. If you took that same shot at 1/100 second, she would be blurred for only 0.088 ft (just over an inch). Crank that shutter speed up to 1/1000 second, and she would appear frozen on the frame (blurred for only 0.1 inch).

Without examples of naked females running up and down the beach taken at different shutter speeds, we will settle for using water movement. The examples show that a slow shutter or a fast one can make a great image, albeit different looking. You are looking at the water in these images, right?

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  A slow shutter speed records the water moving, blurring it into a silky smooth stream

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  VanessaB making a splash, and the fast shutter seems to freeze her and the water movement into droplets

On many cameras, you can control the shutter speed for the exposure. On Shutter Priority, TV or S depending on your camera manufacturer, you can tell the camera the shutter speed and have it determine the aperture/f-stop. You might want to freeze the action or let it blur.

Hand-holding a camera (no tripod or other rigid support) requires a fast shutter spped. People cannot hold a camera for a full second without moving a little. The more you are zoomed in on a subject (telephoto), the more difficult it is to hold still. The rule of thumb for how slow you can hand hold a camera is 1/focal length - if you use good technique. Your typical 10x zoom may require 1/500 or faster shutter speeds. Many camera have image stabilization (or vibration reduction) to allow the photographer to shoot at slow shutter speeds, perhaps 4 times as slow (1/500 becomes 1/125 with image stabilization).

Higher ISO settings can high achieve faster shutter speeds, but they also come at the penalty of noise or a grainy effect. Electronic flashes or strobes have a very short duration. If it is the main light source, the subject will be illuminated for just that brief time, acting like an incredible fast shutter speed.

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  A flash froze the water droplets like a fast shutter might

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  Afill-in flash will not necessary freeze motion, like the waterfall

• Motion Blur from Slow Shutter Speed
• 1/60 sec ISO-200 Relatively slow shutter speed results in blurred subject motion

  1/60 sec ISO-200 Relatively slow shutter speed results in blurred subject motion

• 1/250 sec ISO-800 (Four times the ISO, four times the shutter speed)

  1/250 sec ISO-800
  (Four times the ISO, four times the shutter speed)

• 1/500 sec ISO-1600 freezes motion

  1/500 sec ISO-1600 freezes motion