essential skills: photographic lighting
Introduction An understanding of exposure is without doubt the most critical part of the photographic process. Automatic exposure systems found in many sophisticated camera systems calculate and set the exposure for the photographer. This may lead some individuals to think there is only one correct exposure, when in reality there may be several. The exposure indicated by an automatic system, no matter how sophisticated, is an average. Creative photographers use indicated meter readings for guidance only. Other photographers may interpret the same reading in different ways to create different images. It is essential the photographer understands how the illuminated subject is translated by exposure into a photographic image.
Exposure Exposure is the action of subjecting a light-sensitive medium to light. Cameras and lenses control the intensity of light (aperture) and the duration of light (time). The intensity of light is determined by the size of the aperture in the lens and the duration of light is determined by the shutter. Exposure is controlled by aperture and time - intensity and duration. Too much light will result in overexposure. Too little light will result in underexposure. It makes no difference whether there is a large or a small amount of light, the same amount of light for an appropriate exposure is still required.
Overexposure
Correct exposure - Line Mollerhaug
Underexposure
A digital camera set to manual mode cannot automatically alter its sensitivity to light. Exposure must be adjusted manually. This is achieved by adjusting either the intensity (aperture) or duration of light (time) or a higher or lower ISO chosen. Increasing the size of the aperture gives more exposure, decreasing gives less. Decreasing the duration of the shutter speed reduces exposure, increasing gives more.
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