Hi. I have EOS 50(elan 2) and often use Aperture priority with partial metering. If I use centre focusing point, press shutter halfway and lock and then recompose(ie move a little to the right or left)should I be using FE lock or is my exposure setting locked with my shutter pressed halfway? If so why do we need AE lock button? By using this method will my subject always be metered correctly? I'm happy so far!

Thanks

-- Latham Portous (latport@hotmail.com), January 29, 2002

Answers

FE lock is for flash.

AE lock locks the exposure for a few seconds (way too short - the 16 seconds you get with FE lock is a much better time) regardless of whether or not you're keeping the shutter release half-depressed.

Keeping the shutter release half-depressed holds the exposure for as long as you keep the shutter release half-depressed.

Basically, it's the same effect, but you have a choice of two different ways of activating it. Use whichever one is most convenient for you.

-- Steve Dunn (steved@ussinc.com), January 29, 2002.

"should I be using FE lock or is my exposure setting locked with my shutter pressed halfway?"

I think exposure locks with the shutter pressed halfway only in "one shot" mode and in "servo" mode, exposure is not locked.

"why do we need AE lock button?"

Sometimes you want to lock focus on one point, and lock exposure on a different section. 2 buttons makes this easier.

"By using this method will my subject always be metered correctly?"

If you want the metered subject to be rendered as a middle tone in the photo, then yes. This may or may not produce the most pleasing overall results. If the metered subject is much lighter or darker than middle tone (a polar bear for example), adjusting the exposure (adding additional exposure in this case), would be appropriate in most cases (unless you like gray polar bears).

-- Kenneth Katz (socks@bestweb.net), January 29, 2002.