AE, AF, FV locks demystified

While many digital cameras today don't have an FV lock, virtually all have an AE and AF lock. Unfortunately, few digital camera owners know what these locks are, nor that their cameras have them. It's unfortunate because they are extremely useful camera features.

Here's a basic description of each lock:

• AF-L or AFL — Autofocus Lock: When using auto focusing, this locks focus even when the camera is moved to recompose the photo, prior to making the photograph.
• AE-L or AEL — Autoexposure Lock: When using any of the automatic or semi-automatic exposure modes, this locks the exposure settings, even if the light changes or the camera is moved, prior to making the photograph.
• FV Lock —  Flash Value Lock: When using an automatic setting for your built-in or external flash, this locks the power output level of the flash, even when camera is moved, to recompose the photo, prior to making the photograph.

I use these locks often, especially the AF Lock. I consider the AF Lock as essential as the ISO, Shutter Speed, and Aperture exposure controls.