----- Original Message -----
From: "William Sommerwerck" <williams@xxxxxxxxxx>
> "If you use OM4Ti in auto mode and flash set at Super FP, you will only
get
> proper flash control at shutter speed over 1/60s."
>
> There is no "proper control" of the Super FP mode. The flash's output is
> uncontrolled -- multiple bursts that look like continuous output. The
output is
> constant, regardless of film speed, aperture, shutter speed, ambient light
> level, or distance from the subject -- just as if you were using a manual
> flash.
>
You are partially right, I just made it too simply, I know the camera adjust
shutter speed according to flash reflection from the film/curtain. But the
flash is under controlled, the flash duration is from 1/25s to 1/50s on the
OM4Ti and 1/30 ti 1/70s on the OM707. It is depends on the shutter speed
reading from the sensor/2nd mirror reflection (not OTF).
>
> "It is not the shutter speed [that] affects your flash working distance,
it is
> the ambient light intensity. If ambient light intensity is fixed, the
shutter
> speed and aperture is a constant value. e.g. you can only get higher
shutter
> speed by open up the aperture and in this case larger aperture passes more
> light to film."
>
> But it won't have any effect in Super FP mode, because the flash's output
is
> "continuous." You can't get more flash light to the film by opening the
> aperture, because the shutter speed will shorten in the opposite
proportion.
>
That is exactly what I mean, the exposure is constant with any
shutter/aperture combination under a fixed ambient light. Most people think
you can extend the working distance by using higher speed film or use a
slower shutter speed. But in Super FP mode, both are not the parameter to
get longer flash working distance. It is under ambient light controlled, the
brighter the ambient the short flash working distance or the less flash
effect.
C.H.Ling
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