Originally posted by Marc Sabatella BTW, with all this talk about the secondary functions of the AE-L button, I wanted to be sure the *real* purpose *(which was mentioned, but not dwelled upon) is clear: it's what allows you to meter off something that is kind of "average" in lightness/darkness, then reframe your shot so you can et a well-exposed picture of something that is unusually bright or unusually dark. It's the normal way you'd take a picture of someone with the sky, behind them, for instance. Since the sky is so much brighter than the person (unless the sun is shining directly on them), you'll get an underexposed shot if you just point and shoot. But if you point at the ground or something else about the same brightness as the person, hit AE-L, then frame your picture and shoot, you'll get the exposure you probably wanted. When using any automatic exposure mode, this is / should be / can be an extremely common operation, and *that's* why it is on the grp - not to provide a shortcut to protecting files from being erased.
Thanks everyone, that was a great explanation Marc - just what I needed.
Stay tuned for my next NOOB question...