> I've been scouring any sources of information on this subject I can
> find, but haven't found anything specifically relating to the
> combination of evaluative metering used in conjunction with manual
> focus.
Hi Rusty,
Indeed the user's manual is quite shallow on this topic (and much others
=). I own a 50E and I commonly use manual focus with manual selection of
the focusing point.
The issue here is that when you use evaluative metering, not only the
selected FP but also the surrounding segments will influence the
calculation of the exposure.
Even Flash Exposure can be linked to the AIM system, and for me it's a very
useful feature when combined with Flash Exposure Lock.
What I suggest to you is to repeat the test that Ken proposed, but use a
continuous light source instead of daylight (the window that Ken used) [You
cannot rely on daylight for that cause it changes faster that you would
like]
Take a lightbox (or another even light source) and place it in a dim room.
Now, manual focus on it and start playing with the focus point by manually
selecting one and other... some inside the light source, some on the dark
areas (I'm thinking about a EOS-3 as you mentioned, with the -50E you have
only 3 options :-)
At least with the 50E you *must* select the Focus Point manually. With ECF
or auto selection, it actually defaults to the center point when changing
the lens to manual.
The test will show you the difference in the calculated exposures.
You can replace the lightbox (or another broad, uniform light source) by a
little flashlight or another small light source. Do your test again and
realize how the exposure is changing when the selected focusing point is
on, arround and off the light source.
IMHO that's the best to learn about the "misterious" behavior of the AIM
system. :-)
I hope it helps,
Greetings,
Gerard.
PS: You can also test your AIM-Flash capabilities by using white/gray/black
cardboards as targets. Chack your manual on how to link ETTL metering and
the current FP.
PS2: Don't forget to share your findings with us :-) ;-)
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