Interactive Module IXa: Shutter Speeds

By adjusting the shutter speed of the camera--that is, the speed at which the shutter opens and closes allowing light to reach the film--one can either "freeze" the image or allow for different levels of "blur" to dramatize the speed at which an object is moving.

To "freeze" rapidly unfolding events, we often depend on the "fast shutter speeds" of cameras and "fast film." When a camera can capture events in 1/1000th of a second--or even faster using special cameras or strobe lights--it can provide information that would otherwise be lost to human perception.

To expose film correctly, so that your picture is neither too light nor too dark, you need to control the amount of light that enters the camera. Two controls make this possible: the shutter (discussed below), and the aperture (discussed in the "Depth Cues" Unit).

The Shutter controls the amount of light by the length of time it remains open. Each shutter setting is half (or double) that of the next one and is marked as the denominator of the fraction of a second that the shutter remains open: 1 (1/1 or one second), 2 (1/2 second), 4 (1/4 second), and so on through 8, 15, 30, 60, 125, 250, 500, and on some cameras 1000, 2000, and 4000. B or "bulb" setting keeps the shutter open as long as the release button is held down. T or "time" setting opens the shutter with one press or the release, closes with another.(Upton and Upton, Photography, 3ed, pp. 42-45)

Using Marcel Duchamp's famous ready-made, Bicycle Wheel (C.1913) as a convenient demonstration, a comparison between "stasis" and "motion" is illustrated. The image on the left shows the work in its static state. The modified image* on the right shows the effect as if the wheel were set spinning and a picture was taken at about 1/60th of a second.

In the version below, try rolling your mouse over the wheel. The image that is revealed is modified to appear as if it were taken at an even slower shutter speed (approx. 1/15th of a second).

For more tips on shutter speeds go to: http://photographytips.com/page.cfm/386