In simplest terms, exposure refers to the amount of light that the camcorder's lens collects; auto exposure is a system that controls the incoming light to prevent (among other things) over- or under- exposure. An over-exposed shot looks washed out and overly bright, while an underexposed shot looks shadowy and dark. The AE system on a camcorder uses three different controls--white balance, iris opening, and shutter speed--to set the exposure for certain lighting needs and environments.
Certain camcorders come with a number of pre-configured "Program AE" settings--portrait, sports, landscape, etc. The manufacturer programs these settings for optimum picture quality under the given conditions. As with any such pre-determined settings, using them usually means a sacrifice in picture quality for the sake of convenience, since not every setting will conform perfectly to these guidelines.
Last update: 09:18 PM Monday, October 17, 2005