Screw to permanently open shutter at B setting for Compur/Prontor

blee1996 · May 13, 2023

Hi

I'm trying to find out a way to permanently keep a Compur/Prontor type of shutter open on B setting.
I don't know if there is such thing existing that kind of like:

a super short cable release, screwed onto the cable release socket
keep the shutter always open
doe not have anything dangle around like a real shutter release cable

The reason: I'm adapting some medium format (and large format) lens to be used on Fujifilm GFX-50R

One possibility: I saw some Kodak Anaston/Anastar lens in Kodak Flashmatic shutters (Kodak Tourist folder), where the shutter cable socket was covered by a screw, So in theory I could add a short pin inside the socket to permanently enable the shutter. But I wonder if there already exist a more elegant solution than that.

Thank you!

reddesert · May 13, 2023

Do you already have a shutter in hand? The simplest solution is to use a shutter with either a T setting or a press focus lever/button.

It's not clear to me whether you have specific lenses and shutters in hand that you want to use, or you are looking for the most suitable lens/shutter. For example, if you use a lens that fits into a Copal/Compur #0 or #1 shutter, then (with caveats) you can exchange elements into a #0 or #1 shutter that has a T setting or press focus lever. You might even be able to find a bargain on a non-functioning shutter that still can be locked open. But you won't be able to exchange anything into a Kodak Flashmatic shutter as the threads are different.

If you can't use T or press focus, find a very short locking cable release like 3-6" long (these can occasionally be found on old cameras/lenses) and tape the cable to the shutter so it doesn't flop around.

blee1996 · May 13, 2023

Hi, I already have all the lenses and shutters. And unfortunately none of them have T settings.

1) A Voigtlander Vaskar 105/4.5 (triplet) in Prontor shutter
2) A Kodak Ektar 105/3.7 (Heliar) in Flash Supermatic shutter
3) A Graflex Grandagon 58/5.6 in Synchro Compur shutter

None of the above shutter has T setting, but all have B setting.

reddesert · May 13, 2023

The Flash Supermatic shutter may have a press focus button if it was originally intended for use on a 2x3 press camera (which it probably was, unlike say the Ektar on the Kodak Medalist). If it does, it will likely be a button on the side that looks like the one here: https://www.graflex.org/speed-graphic/supermatic.html

If you have one, further searching will reveal how to operate it (it's usually something like hold the button when cocking the shutter or when firing it, to keep the blades open).

The Grandagon is likely in a Synchro Compur #00 with no T setting, but again some of these may have had a press focus mechanism.

6" locking cable releases are still available new, e.g. from B&H.

blee1996 · May 13, 2023

Thank you both.

I was wrong on the Ektar, which actually do have T setting.

For the other two, I will try the DIY method first (short pin + socket cover reused from Kodak Tourist). If that does not work, I will try to get the shortest cable release and be done with it.

Dan Daniel · May 14, 2023

FYI, most shutters have a specific lever inside for B setting. You could open the shutter, find this lever, and bend it so that the shutter would not close after releasing the firing lever when set on B. You would then need to rotate the speed dial off of B to have the shutter close and be functional at other speeds. You'll need to open the front of the shutter and figure out the specifics for each shutter but it's pretty basic. This will save having extra external parts hanging off the shutter block. Just a thought.

Bill Burk · May 15, 2023

I would cut the cable off the end of a cable release and epoxy or crimp the plunger at just the right depth to hold the shutter open at B.

Then you don’t have to make any alteration to the lens/shutter. And you can use the accessory any time you need.

blee1996 · May 15, 2023

Bill Burk said:
I would cut the cable off the end of a cable release and epoxy or crimp the plunger at just the right depth to hold the shutter open at B.

Then you don’t have to make any alteration to the lens/shutter. And you can use the accessory any time you need.

Thanks, I will try this since I happen to have a broken shutter release cable to experiment with.

Patrick Robert James · May 15, 2023

You could also transfer the lens elements to a barrel if you can find one that fits. For example, a lot of Schneider enlarging lenses came in barrels that are direct matches to Copal/SynchroCompur shutters.

Steve906 · May 21, 2023

The prontor SVS and maybe other versions have a means of locking B - built in. Release the shutter at the B setting then without letting go of whatever means you used to open the shutter - turn the speed dial towards a faster speed, it will stop after only a little movement, then you can let go of everything. To let the shutter close turn the speed dial back towards B.

Screw to permanently open shutter at B setting for Compur/Prontor

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