Practical Artistry: Light & Exposure for Digital Photographers

44 Understanding Exposure

Intentional Over and Underexposure

Intentional Over and Underexposure

What is meant by overexposure and underexposure? In-

tuitively, overexposed means that a photo is too bright.

Colors look washed out, and even “blown out” in very

bright areas. An underexposed photo is too dark, so

dark that you can’t see any details because portions of

the photo seem to have become black.

The exposure controls on your camera act as a kind of

valve that regulates the flow of light to your sensor. As

with a simple electrical circuit, if you let too much cur

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r

ent into the circuit, a light bulb on the circuit might

blow out (overexposure). If you don’t let enough light

into the circuit, the bulb might never light up at all

(underexposure).

I

t’s usually pretty easy to see when you review your

photo in the LCD whether significant portions have

been over or underexposed. Most digital cameras will

also display an exposure histogram that you can use to

analyze an exposure, either before or after it has been

captured.

W

hen enabled, the exposure histogram is usually dis-

p

layed above or below a photo displayed in LCD. It

can also usually be displayed in the viewfinder prior

to exposing an image. The black “bars” in the expo

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s

ure histogram show the distribution of light and dark

values. If the bars are tall and clumped over to the left

side in ...