It is no great surprise you find little support in the manuals. However,
there is hope if you can get some help with the electronics or you are
already pretty good at this sort of thing.
If you can use the existing electronics, I suggest doing so, though maybe
with the shutter remote from the circuits for the sake of space.
If you cannot use the electronics (dead or not able to support your
desired range of speeds, etc.), try using a variable voltage power supply
to find how much voltage will just open the shutter. Do not go up too
slowly in an effort to get an exact value; raise the voltage in 5 seconds
or so. The shutter solenoid might not be intended for long-time operation
at full power (who knows!) You can just look to find the correct wires.
I then suggest a circuit which dumps the charge of a capacitor into the
solenoid at maybe double the voltage needed to just open the shutter,
choosing a capacitor with enough capacity to do the job but not a lot more
(a factor of two error should not be too bad.) After this initial burst to
open the shutter, cut back the voltage to a bit more than enough to just
HOLD the shutter open. This voltage most likely will not open the shutter.
Maintain this voltage for variable times according to the range you wish,
of course, not trying to force the thing open too fast in order to reach
unrealistically fast speeds. (If you have a lot to spare, you can push one
to the limit and make the circuit for the next one to stay BELOW the
limit!!!! Please tell us what you find so we can avoid repeating the
experiment.) Typically large format shutters do not offer very short
exposure times and so you should not be disappointed by not reaching 1/500
sec, or even 1/250.
The electronics I describe is not very complex to make so please do not be
frightened by the sound of it. Someday I hope to do this with a Metrogon,
but that has a special problem. The shutter must be very thin over quite a
large diameter to fit between the lens cells. Steve Grimes describes his
method of dealing with this with a mechanical shutter. The original camera
makers used a special, thin shutter and no variable diaphragm in those
aerial cameras having a between the lens shutter. So my project waits for
me to make or adapt a shutter to fit this special case.
If the camera still works you can measure what the manufacturer used; I
recommend an oscilloscope. This will enable you to see any initial high
voltage burst. There may or may not be one.
You can find cameras with purely mechanical shutters. I sold a lens from
one some time ago and know others are offered at ebay. In the past they
were common and I expect they still are frequently offered, with or without
the glass. Often only cleaning will be required to use one, plus the
machining to mount your lens.
Bob
At 12:38 27.07.01 -0400, you wrote:
> Some of the better '70s - '80s oscilloscope cameras had fairly wide
>mouthed shutter assemblies (from which I've stripped the macro lenses).
> Thanks! Joe Meyerson
Dr. Robert Mueller
Institut für Festkörperforschung, FZ-Juelich
D-52425 Juelich, Germany
phone: + 49 2461 61 4550 FAX: + 49 2461 61 2610
email: [EMAIL PROTECTED]
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