Digital Photography in Available Light

(National Geographic (Little) Kids) #1

creative controls


A creative decision


The choice between depth of fi eld and shutter speed is often a compromise. Choosing one effect
impacts upon the other. The need for correct exposure requires the photographer to make one
effect a priority over the other. When the photographer requires overall focus, movement blur
is likely to occur from the use of a slow shutter speed. When the aperture is opened to achieve
shallow depth of fi eld the shutter speed is relatively fast. Movement blur is unlikely unless the
photographer is photographing in subdued lighting conditions. Similarly when the photographer
requires a reasonably fast shutter speed to avoid camera shake or freeze motion, shallow depth
of fi eld is often the result.


Limitations of semi-automatic
When selecting shutter priority mode on a built-in metering system the photographer must take
care not to underexpose images. Excessively fast shutter speeds for the available light may
require an aperture greater than that available on the lens.
When selecting aperture priority mode on a built-in metering system the photographer must take
care not to overexpose images. Excessively wide apertures to create shallow depth of fi eld in
bright light may require shutter speeds faster than that available with the camera being used.


ACTIVITY 5
Record the widest aperture available on your lens or lenses when photographing in bright
sunlight using an image sensor rated at 100 and 400 ISO that does not lead to overexposure.
Record the fastest shutter speeds available when photographing in a variety of interior locations
using the existing light only.
Create an image that contains a mixture of solid (sharp) and fl uid (blur) form.

Orien Harvey
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