What is Shutter Speed? In very simple terms, shutter speed is the time it takes for the shutter on the camera to open and close. When the shutter is open, light is let in to the sensor and when it is closed, no light gets in.
The longer the shutter is open, the greater the amount of light that is let in. The more light, the brighter your image will be.
Conversely, the shorter the shutter is open, the less light that is let in.
Shutter speeds are typically recorded in fractions of a second: second is a long shutter speed (more light) and 1/1000 is a short one.
Usual values are: 1 - 1/2 - 1/4 - 1/8 - 1/15 - 1/30 - 1/60 - 1/125 - 1/250 - 1/500 - 1/1000
There is also often a B (or bulb) setting which allows the user to hold the shutter open for as long as they wish. In addition, digital cameras often have shutter speeds in-between the values shown above and can also often be set for 10, 20 or 30 seconds.
With a fast shutter speed, the shutter is open for only a short time. This helps especially in two ways. First, it helps to freeze the movement of a fast moving subject. Secondly, it reduces the chance of camera shake. A slow shutter speed will allow blurring of movement and will enable much smaller apertures to be used.
Of course, shutter speed settings are combined with aperture settings in setting the amount of light that comes into the camera. You can see it as the aperture determining the intensity of the light hitting the sensor and the shutter speed determining how long it hits the sensor for.
Eric Hartwell runs the photography resource site http://www.theshutter.co.uk and the associated discussion forums as well as the regular weblog at http://thephotographysite.blogspot.com
