If you are trying to photograph in tricky lighting, causing lots of variation between bright and dark areas on subject? Are you not sure what exposure setting be appropriate?
You can adjust exposure manually to get the shot right, but it will take great deal of time, as you have to take a number shots manually to get every thing correct. The moment you aim to photograph might be lost in middle of this trials.
Now a days most DSLR and high-end point and shoot cameras are equipped with a feature called ‘Automatic Exposure Bracketing (AEB)’ which can save your precious time in these situations.
Automatic Exposure Bracketing or AEB will take three shots at different exposures automatically without manual intervention. Have a look at the pictures below,
If you select AEB, camera will select an exposure based on its best guess then it will take additional two shots on both side of the best guess. Here that resulted in three shots one is normal and others are over and under exposed.
You can set camera in continuous shooting mode (burst mode) to take three shots consecutively with single shutter press. But if your camera is in single shot mode, you have to press shutter three times.
Where to select Automatic Exposure Bracketing entirely depend on camera manufacture and model. So please refer you camera manual to understand the settings.
Also most of the camera will allow you to change variation of your shots by different ‘stops’. To have a big variation you can go with 2 stop-gap or you can go with 1 stop to have small variation.
If you want more control over Automatic Exposure Bracketing mode you can use Aperture Priority mode or Shutter Priority mode. In Aperture Priority Mode you can fix an aperture and tell the camera to make variations in shutter speed. Or you want shutter speed to be fixed, go with Shutter Priority Mode and vary exposure by changing the aperture in your shots.