Automatic Exposure Bracketing (AEB) – A camera function that photographs continual photos at different shutter speeds and the aperture and ISO are constant. Generally, the photos are taken at three to five different shutter speeds; hence the term bracketing. The concept is to have one of the bracketed photos correctly exposed for use.
When you don’t know what exposure compensation to set, then use AEB.
When you have three bracketed photos: one photo will be under-exposed; one photo will be normally exposed or considered normal; the last photo will be over-exposed. The under-exposed photo helps image the details of a bright scene by making it darker. The over-exposed photo helps image details of a dark scene by making it brighter.
This method of taking photos is the stepping stone to high-dynamic-range photography (HDR), where each of the bracketed photos are used and combined into one. HDR retains more detail (dynamic range) than a single photograph.
Look at the below photos. The camera settings are constant due to AEB, except for the shutter speed. Pay attention to the details of the buildings and clouds at different shutter speeds (exposure compensation).