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Re: [OM] multiple flashes

Subject: Re: [OM] multiple flashes
From: Pauls0627@xxxxxxx
Date: Tue, 6 Oct 1998 10:01:57 EDT
In a message dated 10/6/98 9:45:55 AM Eastern Daylight Time,
williams@xxxxxxxxxx writes:

<< There is no reason, in principle, why you couldn't wire the trigger and
 quench circuits of several F280 flashes in parallel. When the shutter is
 released, all the flashes would fire. When the in-camera sensor detects
 enough light, the quench signal would shut all of them off.
 
 In practice, there is a limit as to how many flashes the quench signal
 can drive (for exactly the same reason there is a limit to how many
 speakers you can connect to an amplifier). You also run into a problem
 if you use a long cable -- the cable capacitance could so reduce the
 rise time of the quench signal that the flashes cut off late -- or not
 at all. It's also possible that the F280 uses some Really Weird circuit
 that would be damaged by parallel operation.
 
 I am not suggesting that anyone run the risk of damaging their flashes
 by trying a parallel hookup. Still, I wonder why Olympus proscribes such
 a hookup. I'd like to hear from them about this. >>

If you're talking about "normal" TTL flash, I would agree. However, for Super
FP flash, I dont think the camera actually quenches the flash. There was a
thread on this a while ago, and I think it was said that for Super FP flash
the flash illuminates for the full duration of the exposure. In the case of
the OM-4Ti (and OM-77/707, I guess) the camera's meter controls when the 2nd
curtain begins closing, but not the duration of the flash. On the OM-3Ti since
the shutter is mechanically goverened, you need to do an old-fashioned manual
GN calculation. It's not clear to me how this would interfere with multi-flash
control. It would seem that it's a matter of propogating the synch signal to
the multiple flashes. Maybe the OM-3Ti/OM-4Ti couldn't handle the current
generated by multiple flashes? Just a guess.

Paul Schings
Coventry, RI

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