In a message dated 98-04-13 14:17:07 EDT,
Richard you write:<< > << the image projected on the shutter curtain patern.
Does the OM-3Ti have a pattern on the shutter curtain?
Does it? If I remember right, there is no patern on the shutter.
Snip!
Well, I've got film in my 3Ti so I'll check the curtain in a few days and let
you know.
> Is there someone who knows how the FP exposure is calculated? >>
OM-4Ti catalog says, that the flash time selection is coupled with the
aperture.
Snip!
Yes, this is in the 4T 1984 catalog as well.
Additionaly there is no way to change the FP flash output after the
shutter has started.
Snip! I Agree. I think??
The conection with the aperture is necesary because otherwise there
would be the danger of over flashing if the object is near, the aperture
wide open and the shutter time relativly long (for expl. 1/80 in a dark
stuation). The catch is, that the camera has no info of the aperture,
just a relative info how many stops the lens will close.
Snip! OK, I'm with you so far! So if I really want to screw this flash up,
just shoot at close range with a wide open aperture?
The FP flash time is always longer than the sync time, that sugest, that
the flash starts before the shutter in Auto mode.
An posibility for adjusting the FP flash output would be, that the flash
starts after the mirror is up and the aperture has closed, mixing the
flash light with ambient light.
Snip!
So the OTF meter would choose the power (20 ~40 milliseconds)of the flash?
That would explain why the new 3Ti does not have this feature. It has to be
set manually by using a guide# chart because it does not have OTF metering and
probably fires at full (40 milliseconds) power?
The OM-4Ti (OM-77AF and OM-707 too?) is now able to chose an shutter time
which avoids overexposure. If the OM would measure the ambient light before
the flash starts, it could balance flash light to ambient light.
Snip!
Am I right?
YES, It is starting to make a little since.
So, the OTF meter controls two(2) functions. 1) The power output of the flash
(20~40 milliseconds) after the shutter opens and the aperture stops down. 2)
The shutter speed will balance the ambient + flash light for proper exposure.
Therefore, at close-up ranges (18 inches to 48 inches) the flash output can
very according to the f stop chosen and ambient light controled by the OTF
meter and a shutter speed will be chosen to balance exposure. This shutter
speed could INCREASE(1/500 sec) or even DECREASE(1/60th sec) depending on the
f stop, balance of the ambient + flash light and distance from lens.
So, I should consider this Super FP mode with camera in Auto as a fill-in
flash with scync speeds in the 1/60th to what ever, 1/125 or so. If I want to
use higher shutter speeds ie. 1/1,000 or 1/2,000 second, then I will need to
work out guide #'s distance/ f stop combinations for short close-up ranges
with the camera in manual mode.
Richard, Thanks alot for helping me "see the light " a little better. I owe
you.
The Not so Dummy Now!
BW
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