Lester Wareham wrote:
Exactly. If you leave CF4 on 0 and adjust the focus manually and then> Two Questions regarding Canon DSLRs (in particular the 20D):
> a) Is it necessary to set the Custom Function 04 to 1 (AE Lock / AF)
> in order to use the full time manual focus feature of most USM AF
> actuator fitted Canon lenses? (If AF lock is on the shutter can you
> not use full time manual focus because the AF algorithm is fighting
> the manual changes - I don't know)
press the shutter release, the AF will adjust to what it thinks is
good. So the first thing I did on my D30 and now on the 20D is to
program CF4 to either 1 or 3 (difference comes below)The * button then is for the AF only and the shutter release is for AE.>
> b) If you set Custom Function 04 to 1, what happens about FE lock?
> Does FEL still occur on the * button or on the shutter release (along
> with AE lock)?
If you set CF4 to 1, the the shutter release will work as AE lock (Tv,
Av, P mode, of course not M, does anybody use the other settings?). Aim
at some dark areay, half press the shutter release, keep it down and
turn the camera to some light area and watch the displayed values for
time and aperture. They will stay at the values of the dark measuring
point. That AE lock and is indicated by the '*' in the viewfinders
If you put CF4 to 3, then AE is not locked. Do the same as before and
you will notice that time and aperture are adjusted while turning the
camera. This is great if you are following some moving object, i.e. a
car that is passing in front of light and dark backgrounds.
So if you need AE Lock, use CF4-1, else CF4-3. You quickly get used to
have AF on the * button. BTW, on the 20D, I now use mostly the AF as
it's excellent working even in quite dark surroundings, on the D30 it
was often necessary to use the FTM of the lenses as the D30's AF barely
deserves it's name.