Wednesday, June 11, 2008

Creative Utility in Photography

Shutter speed is one of several methods used to control the amount of light recorded by the camera's digital sensor or film. It is also used to manipulate the visual effects of the final image beyond its luminosity.

Slower shutter speeds are often selected to suggest movement in a still photograph of a moving subject.

Excessively fast shutter speeds can cause a moving subject to appear unnaturally frozen. For instance, a running person may be caught with both feet in the air with all indication of movement lost in the frozen moment.

When a slower shutter speed is selected, a longer time passes from the moment the shutter opens till the moment it closes. More time is available for movement in the subject to be recorded by the camera.

A slightly slower shutter speed will allow the photographer to introduce an element of blur, either in the subject, where, in our example, the feet, which are the fastest moving element in the frame, might be blurred while the rest remains sharp; or if the camera is panned to follow a moving subject, the background is blurred while the subject remains sharp.

The exact point at which the background or subject will start to blur depends on the rate at which the object is moving, the distance it is from the camera and the focal length of the lens in relation to the size of the digital sensor or film.

When slower shutter speeds, in excess of about half a second, are used on running water, the photo will have a ghostly white appearance reminiscent of fog. This effect can be used in landscape photography.

Zoom burst is a technique which entails the variation of the focal length of a zoom lens during a longer exposure. In the moment that the shutter is opened, the lens is zoomed in, changing the focal length during the exposure. The center of the image remains sharp, while the details away from the center form a radial blur, which causes a strong visual effect, forcing the eye into the center of the image.

Shutter speed can have a dramatic impact on the appearance of moving objects. Changes in background blurring are apparent from the need to adjust the aperture size to achieve proper exposure.

Slow shutter speed combined with panning the camera can achieve a motion blur for moving objects.

A photo of sparks coming from coals (exposure time 15 seconds)

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