density of the image recorded can be altered through single stop
gradations from +1,+ or -1,-2 stops. Because this is not achieved
through an aperture but by varying
the voltages recorded when the light falls on the sensor there
is no affect to the depth of field in the resulting image.
exposure (+) This is useful where the subject might be back lit,
and needs more exposure to bring out the detail in the subjects
face, or where the situation is dark.
Under exposure (-) This is useful where the situation is very
bright like at the beach or in the snow where you might like to
bring out more texture in the subject.
The exposure control can alo be used to create mood in an image.