Digital Cameras: What is the AE Lock?
The AE lock on your digital camera is an abbreviation for auto exposure lock. Most photographers use auto exposure at some point to help them shoot fast. The AE lock offers them greater control over their images, without sacrificing speed. What it does is freeze the auto exposure so it remains constant, while you're shooting until you unlock it.
Understanding the AE Lock
This is beneficial because it does not hinder your work pace. Sometimes photographers are in a situation where they need to shoot fast and can't keep manually changing the exposure, so they let the camera automatically do it. The auto exposure lock helps the photographer maintain control. Perhaps the auto exposure is a little brighter than he likes; he can lock the AE before it reaches that point. As they travel from situation to situation, they can unlock the auto exposure to compensate for changes.
It can also be used in situations where there is so much light that the AE causes the image you want to capture to appear too dark. You can point the camera at the ground, set the AE lock, then aim and shoot with the exposure you want. AE lock is available in most digital cameras.