When Automatic Exposure Works Well
Most scenes that you photograph have an overall brightness of middle gray. Some areas of the scene may reflect 90% of the light and other parts may reflect 5%, but overall the average amount of light reflecting from the scene is 18%, the amount reflected by a middle gray subject.
Whenever you photograph a normal scene with this average brightness, your automatic exposure system exposes it correctly. Typical middle gray scenes include the following:
- Scenes in bright sunlight where the subject is front-lit by a sun that is behind you when you face the scene.
- Scenes on overcast days or under diffused light, such as in the shade or in evenly lit scenes indoors.
This landscape of Canyon de Chelly was taken on an overcast
morning using autoexposure.
This portrait, taken under a cloudy bright sky is perfectly exposed with autoexposure.