Using a Speed Graphic Focal Plane Shutter in other LF cameras for barrel lenses?

[Asher Kelman]

For studio work dependent almost entirely on flash for lighting, a accuracy of the shutter speed is not important. For natural light and long exposures, the cap-uncap Galli method would work too. Between these extremes, a shutter for barrel lenses would be wonderful. I now need this to mount in the wall for a walk-in camera obscura I'm making. I'll be using this for Apo lenses such as the Nikkor 760mm, Germinar 750mm, Red Dot Artar 47 1/2 inches.


Keery Thalmann suggested to me that one can repurpose the focal plane shutter of a Speed Graphic for barrel lenses in other LF cameras. What a great idea!

1. Has anyone done that and can share pointers on repurposed Speed Graphic or similar shutters? It's a painful thing to rip apart a perfectly good speed Graphic. Still, it seems to be a very brilliant way of getting a shutter, way more advanced than a Packard, for so many different lenses. So, what are the limitations in the diameter of lens for such use? Is there a shutter workshop that you know has done this? Of course, I will ask SK Grimes, but perhaps someone already has experience and a straightforward solution or even another newer focal plane shutter that could be adapted.


2. Thornton Pickards: I'll add that I own a bunch of Thornton Pickard shutters but I fear the cords breaking. In fact one did when I was testing it! If they can be reliably repaired, then that would be great. I'll call Carol of Flutot when they open this afternoon.


3. Any effect of lens diameter and focal length on front camera mounted curtain shutters? Does the curtain shutter of a speed Graphic or Thornton Pickard in front of the lens or behind the lens standard give different speeds with different diameter lenses and focal lengths or to the various factors cancel themselves out? I know front-mounted Packards are used with the Apo Germinar 750mm, but then is the speed different dependent on lens use when a larger diameter lens is fitted instead?

This subject was brought up here discussing a so-called Focal Plane Shutter, (a gravity driven shutter that fits on the front of a lens), but the matter of whether shutter speed raised there and seemed to be a valid objection. After all, a small aperture lens would have a shorter time for passage of light than a wide lens!

So, does one need correction factors for the different barrel diameters and focal lengths for any front-mounted curtain shutters?

Thanks,

Asher

For the hi-tech folk, I did check on an LCD shutter, but they are limited to very narrow angle work or else the reflections and scatter floods the camera with unwanted diffuse light! Still, there may be something that will appear and if you find it, tell us!

[rdenney]

I have the carcass of a quarter-plate Pacemaker Speed Graphic that may someday become a project like this. I would mount the box backwards behind the front standard of a monorail view camera, probably fashioning a way to mount it Sinar-style so I can put it on my Sinar F. The smaller size would be plenty big enough for nearly all barrel lenses that can be mounted far enough forward.

Realize that you are limited to faster speeds only. The slowest my Pacemaker-era shutter will go is 1/30. Slower than that, and you need a felt had over the lens. That leaves a pretty big gap for a lot of large-format work, it seems to me. If the lens is one of those super-fast aero-ektars, though, it won't be a problem.

It's a little down on my project list, however. And if I found myself with an extra half a kilobuck, a Sinar Copal shutter would be a far more elegant solution.

Of course, you can always mount a barrel lens on a Speed Graphic.

Rick "not really sure it rises above doing it just because it can be done" Denney

[Asher Kelman]

I have the carcass of a quarter-plate Pacemaker Speed Graphic that may someday become a project like this. I would mount the box backwards behind the front standard of a monorail view camera, probably fashioning a way to mount it Sinar-style so I can put it on my Sinar F. The smaller size would be plenty big enough for nearly all barrel lenses that can be mounted far enough forward.

Realize that you are limited to faster speeds only. The slowest my Pacemaker-era shutter will go is 1/30. Slower than that, and you need a felt had over the lens. That leaves a pretty big gap for a lot of large-format work, it seems to me. If the lens is one of those super-fast aero-ektars, though, it won't be a problem.

It's a little down on my project list, however. And if I found myself with an extra half a kilobuck, a Sinar Copal shutter would be a far more elegant solution.

Of course, you can always mount a barrel lens on a Speed Graphic.

Rick "not really sure it rises above doing it just because it can be done" Denney

Thanks, Rick!

Asher

[domaz]

Adapting a Sinar Shutter might be a better idea. It has slow speeds too which makes it much more usable than a Speed Graphic IMO. KEH has a whole flurry of Sinar Shutters right now. Some for well under a "kilo-buck".

[Jim Jones]

A 4x5 Anniversary SG with speeds down to 1/10 could be cut down and kludged onto a reversing back for many 4x5view cameras. This provides some extension for those long barrel lenses, too. One might also convert it to a Graflok back. A SG in original configuration is a great camera, but sometimes does even better when extensively modified. The Anniversary shutter may be friendlier to the amateur mechanic than the Pacemaker version.

[Asher Kelman]

Adapting a Sinar Shutter might be a better idea. It has slow speeds too which makes it much more usable than a Speed Graphic IMO. KEH has a whole flurry of Sinar Shutters right now. Some for well under a "kilo-buck".

Thanks so much, Domaz,

Those Sinar shutters are very much a bargain if they do the job. There's a nice discussion on using the Sinar shutter here. I still have to find the specs to see what diameter it can go to.

Does it account for the diameter of the lens or is it "One shutter speed fits all!"

Asher

[Asher Kelman]

A 4x5 Anniversary SG with speeds down to 1/10 could be cut down and kludged onto a reversing back for many 4x5view cameras. This provides some extension for those long barrel lenses, too. One might also convert it to a Graflok back. A SG in original configuration is a great camera, but sometimes does even better when extensively modified. The Anniversary shutter may be friendlier to the amateur mechanic than the Pacemaker version.

Thanks, Jim,

I don't mind a bit of complexity! It's the best shutter solution! Which is the best made most accurate shutter for this purpose?

Asher

[Steven Tribe]

I have twice seen the focal plane section and 4x5" a back from a Speed Graphic mounted on the back of a mahogany plate to fit a larger camera, on offer on that auction site. Very well done too, in both instances. The separately sold rear focal shutters from F&S are, unfortunately, rare and expensive.

[Jim Galli]

Domenico Foschi had one like this that he used on a Kodak 2D 8X10. It was big clunky ungainly and a huge stress on the front standard which had to hold the weight of the mechanism and also account for the heavy brass lenses now being cantilevered out in front.

Also when it is in front you are NOT getting the advertised speeds. I once calculated that the eighth inch slit on one of those actually takes about 1/12th of a second to travel. At the focal plane right next to the film that means that during that time only the fraction of the film directly in front of the slit is being exposed. Out in front of a lens the light will go through the slit and fan out everywhere. I don't know how to calculate what an effective shutter speed would be in that case. Easier on a movie camera where you have knowns like shutter angle and rotation speed to work with.

Another thought; with a moving slit you cannot have any flash sync., something that seems to me would be a show stopper for your application. Far easier to let the flash decide the speed than fiddling with shutters. Packards and Sinar's can sync up easily with flash.

All of that aside, it did in fact work and Domenico got excellent results with his. Me, I've learned to live within the constraints of a Packard's 1/25th speed which is quite repeatable. The Sinar is far more elegant.

[Asher Kelman]

Domenico Foschi had one like this that he used on a Kodak 2D 8X10. It was big clunky ungainly and a huge stress on the front standard which had to hold the weight of the mechanism and also account for the heavy brass lenses now being cantilevered out in front.

Well, Jim,

If Domenico's camera withstands the weight, for sure my wall will hold it, LOL!!

Also when it is in front you are NOT getting the advertised speeds. I once calculated that the eighth inch slit on one of those actually takes about 1/12th of a second to travel. At the focal plane right next to the film that means that during that time only the fraction of the film directly in front of the slit is being exposed.

That's what I was worried about!

Out in front of a lens the light will go through the slit and fan out everywhere.

That I didn't think of!

Another thought; with a moving slit you cannot have any flash sync., something that seems to me would be a show stopper for your application.

So that's clarified and important info and much appreciated!

Far easier to let the flash decide the speed than fiddling with shutters. Packards and Sinar's can sync up easily with flash.

But the shutter transit time will be shorter for a narrow lens barrel, but I can calculate and even measure that.

All of that aside, it did in fact work and Domenico got excellent results with his. Me, I've learned to live within the constraints of a Packard's 1/25th speed which is quite repeatable. The Sinar is far more elegant.

Which Sinar shutter to choose that will take barrel lenses of the size I am using?

It seems that I should think of getting SK Grimes to make a series of slip on adapters for one Packard shutter. It seems that one really needs to measure the shutter speeds for each lens anyway.

Thanks, as always, Jim for your sharing of your experience!

Asher