Monday, October 1, 2012

SHUTTER and SHUTTER SPEED


Shutter
The shutter is a complicated mechanism that precisely controls the duration of time that light passing through the lens remains in contact with the digital image sensor. The camera’s shutter is activated by the shutter release button. Prior to the digital age, the shutter remained closed to prevent the film from being exposed.
Depending on the type of digital image sensor, a mechanical shutter may not be necessary. Rather than a shutter revealing light to initiate a chemical reaction in the film, the digital image sensor may simply be turned on and off.

Shutter Speed
Shutter speed refers to the amount of time the shutter is open or the digital image sensor is activated. The exposure of the image is determined by the combination of shutter speed and the opening of the aperture. Shutter speeds are displayed as fractions of a second, such as 1/8 or 1/250. Shutter speed increments are similar to aperture settings, as each incremental setting either halves or doubles the time of the previous one. For example, 1/60 of a second is half as much exposure time as 1/30 of a second, but about twice as much as 1/125 of a second. Photographers often use shutter speeds to convey or freeze motion. A fast-moving object, such as a car, tends to blur when shot with a slow shutter speed like 1/8. On the other hand, a fast shutter speed, such as 1/1000, appears to freeze the blades of a helicopter while it’s flying

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