Giant shutter?

[genotypewriter]

Hi everyone,

I'm looking for a shutter with an opening of at least 5" (127mm) that can do fast shutter speeds. I've spent a lot of time thinking about this and here are some points:

• Opening and closing the lens with a cap is not an option
• Custom Packard shutters are not possible due to both price and the limitation to 1/25 or so. I need the shutter speed to be adjustable.
• DIY is an option and I've thought about guillotine shutters, rotary shutters as well as focal-plane-like shutters. The main problem I have is controlling speed.
• The shutter can sit any where really. Assume that this is for a DIY 8x10 camera.

Any suggestions would be much appreciated!

[Old-N-Feeble]

Some folks gut an old 4x5 Speed Graphic for the focal plane shutter... speeds from 1 sec to 1/1000 plus T. But that's 4x5, not 5x5.

[IanG]

A Thornton Pickard focal plane shutter has a top speed of 1/1000 so should be fast enough, a bit rare though in any size.

Ian

[Jim Michael]

A guillotine shutter where you have a constant pulling force from a spring should allow control of shutter speed via slit width. I'd probably add some type of mechanism to reduce friction in the moving components like roller bearings, perhaps an ME would have a suggestion.

[ic-racer]

You may be able to make a large Magneto-optical shutter or Kerr Cell shutter.
http://webmuseum.mit.edu/browserview.php?kv=70151

[cosmicexplosion]

what lens/film configuration/application are you using/doing that needs faster than 1/25, just curious.

i recently aquried a 300mm aero ektar 'f2.5' so i am also, trying to find a large shutter.

"got me the shutter bug blues"

[Dan Fromm]

It pains me to bring them up because they're not common and shouldn't be destroyed, but there are 5x7 Speed Graphics (press cameras) and Graflexes (SLRs) with focal plane shutters.

Knowing what OP is trying to accomplish (lens' focal length and maximum aperture; shooting situation = film speed, desired aperture/shutter speed combination, image circle required) would be helpful. Some things just can't be done -- I suspect the OP has constrained himself into infeasibility, hope this isn't so -- but sometimes the apparently impossible can be done.

[genotypewriter]

Some folks gut an old 4x5 Speed Graphic for the focal plane shutter... speeds from 1 sec to 1/1000 plus T. But that's 4x5, not 5x5.

Yes, I got one for that exact reason to use on a 48cm f/4.5 Xenar but then I found a bigger lens

A Thornton Pickard focal plane shutter has a top speed of 1/1000 so should be fast enough, a bit rare though in any size.
Ian

That's an excellent suggestion, Ian. Didn't know about such a thing. Looking at what's up for sale, the shutters don't seem to be in good shape though.

A guillotine shutter where you have a constant pulling force from a spring should allow control of shutter speed via slit width. I'd probably add some type of mechanism to reduce friction in the moving components like roller bearings, perhaps an ME would have a suggestion.

I already made one with a relatively high torque 12V DC motor. The problem is making a variable slit shutter that's light enough to be pulled by the motor with the least amount of acceleration and not fragile at the same time.

You may be able to make a large Magneto-optical shutter or Kerr Cell shutter.
http://webmuseum.mit.edu/browserview.php?kv=70151

Reading up on it, it looks like there will always be glass in the middle. Will keep this in mind for a different project

what lens/film configuration/application are you using/doing that needs faster than 1/25, just curious.

i recently aquried a 300mm aero ektar 'f2.5' so i am also, trying to find a large shutter.

"got me the shutter bug blues"

Same lens...

It pains me to bring them up because they're not common and shouldn't be destroyed, but there are 5x7 Speed Graphics (press cameras) and Graflexes (SLRs) with focal plane shutters.

Knowing what OP is trying to accomplish (lens' focal length and maximum aperture; shooting situation = film speed, desired aperture/shutter speed combination, image circle required) would be helpful. Some things just can't be done -- I suspect the OP has constrained himself into infeasibility, hope this isn't so -- but sometimes the apparently impossible can be done.

Thanks, Dan. To answer your questions...

Focal length: Anywhere from 300 to ~500mm or maybe longer in the future. I intend to use this for several lenses.
Maximum aperture: The largest lens I have right now has a 120mm aperture. If you're wondering about the light transmission, it's around f/3.5.
Shooting situation/film speed: ISO100, on field.
Desired shutter speeds: As fast as possible. 1/500 if it's not too ambitious.
Image circle required: 8x10... so it's easier to install the shutter on the lens than on the focal plane.

Thanks again for everyone's suggestions.

[IanG]

Depending on the lens size one of the larger standard Thornton Pickard roller blind shutter (or similar) may be OK, I have a couple that would work with a 120mm diameter front/rear diameter lens. While these are usually 1/15th to a 1/90 there were higher speed versions - essentially they just need a narrower slit - would need to be front mounted in this case but 1/400th is possible. These do come up for sale occasionally or I get mine from camera fairs etc. I restored 3 larger ones last Spring.

If you found a Focal plane version with all its brass work then restoration is relatively easy. TP also made 10x8 cameras with built in FP shutters.

Ian

[Dan Fromm]

Hmm. 300 mm lens, 300 mm circle, 1/500. Hmm. According to a stupid little similar triangles model that I use to help me think about front-mounting, that can almost be done with a #1 close behind the lens.

A Compur/Copal/Prontor 1's maximum opening is 30 mm, lens' rear node-to-infinity is 300 mm, the circle covered is 300 mm. If the rear node-to-shutter distance is no more than 30 mm the shutter will vignette the circle to no less than 300 mm.

If you think hard about my little model you'll see that it isn't quite right. That said, I've shot a 480 Apo Nikkor on my tandem 2x3 Graphic with no vignetting. Filled the 2x3 frame with good image, corners weren't darker than the center.

There's a minor(?) snag with this approach when applied to lenses with large apertures. Basically the lens' diaphragm will have no effect on exposure -- the lens will effectively be at full aperture -- until the exit pupil is the size of the shutter's maximum opening.

The big idea here, OP, is that the shutter doesn't have to be as large as the lens' maximum aperture or the exit pupil if it is close to the lens. Don't scoff, try it.