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Re: [OM] T and FP sync

Subject: Re: [OM] T and FP sync
From: VELUWEH@xxxxxxxxxx
Date: Thu, 29 Oct 1998 12:02:27 -0500
Foxy wrote:

>I've got a question for the medium format people out there. What is the
>T shutter speed setting?

Although I'm not a medium format person (I've been treated for that :-)
I think I can still explain it. It's simular to the 'B' (for 'Bulb
Exposure') setting. The difference is that a 'T' (for 'Time Exposure')
setting stays open untill you press the shutter again. A cable release
with a lock option provides an OM also with 'T' facilities :-)

>Also, the OM-3Ti and 4Ti do this high speed flash sync thing.
Therefore,
>a FP type signal must be sent to the hot shoe to trigger the flash
prior
>to the shutter opening. So, can we use a FP sync signal from a 1(n) or
>2(n) to trigger the F280 flash and have high speed sync on the old
>models? After all, the high speed sync is simulating a flash bulb
>anyway.

AFAIK there's a big difference in the FP activation on the PC flash
connector on an OM-1 or OM-2, and the F280 activation contacts in an
OM-4Ti or OM-3Ti. The first one just connects the two contacts prior to
curtain movement. There is no voltage, so it also works with a
batteryless OM-1. The F280 signals however do work with some voltage -
the flash doesn't fire by just shortcutting the contacts.
So I'm afraid you still have to look for a real FP lamp to get things
working on an OM-1 or OM-2. In a flash book from the 70's I have
there's a table showing various bulbs Philips produced in those days.
Among them where FP bulbs with very high power - GN's of over 100
meters at 1/125 sec (decreasing rapidly with shorter shutter speeds).
Something to learn from, Olympus, with this miserable 28... :-(

>Or can we use a signal from the 3/4Ti to trigger a flash bulb?

Only a regular X bulb, activated from their PC connectors, with shutter
speed set at 1/30 or longer. I don't think the F280 pins can activate
an FP bulb.


Hans

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