Slip on focal plane shutter

[Gordon Moat]

It would be quite nice to see this shutter tested for View Camera magazine. Perhaps someone can lead the way to make that possible. Speculation one way or the other without actual data serves no purpose beyond fueling arguments. On a very simple presumption, gravity changes very little with altitude, and can be considered reliable; considering that many shutters are off a bit at each setting, I would rather know accuracy of settings than other claims. The slit width idea has been used many decades in focal plane shutters, so the basic idea of that is not new.

I would prefer to see something like this on the market, than to see no solution. Some here address this in such a manner that it seems they would rather kill off such ideas. Yet when products do disappear, is it any surprise when people bitch about the lack of innovation or attempts to make anything. If this is the place for Large Format, then the voices of discouragement are louder than encouragement. I think that is quite sad and a poor reflection upon this forum.

Criticism can lead to better products, but only if it is constructive. This product does compete with older leaf shutters, and I do think pricing is a consideration. However, compare this shutter to a Packard, and I think we would find different viewpoints. Does anyone here actually want this type of shutter in the market? I do.

[don12x20]

Criticism can lead to better products, but only if it is constructive. This product does compete with older leaf shutters, and I do think pricing is a consideration. However, compare this shutter to a Packard, and I think we would find different viewpoints. Does anyone here actually want this type of shutter in the market? I do.

I agree, Gordon.

I do want this shutter to succeed as well.

I certainly don't need it for any of the modern glass I have.

Yet there are many of us that have many older pictorialist lenses that have no shutters what-so-ever. While we're adept at using cards (in a handheld slit arrangement much less accurate than what Ron offers!), hats, berets, lens caps, and even the Packard Shutter with its maximum of 1/25th second, ...all of us dream of using faster films (even 100 ASA) with these lenses in normal lighting conditions, and that requires a faster shutter (or wait for dark and use 25 ASA Efke film).

So, Ron, continue to develop your shutter. Make it -- but a little larger in diameter-- and they will come.

Don't fall prey to the few whiners that can't comprehend what you are trying to implement, or that you aren't competing at all with modern shutters. There is actually a market for it for anyone that has a Petzval, Pinkham, Cooke, Ross or Verito.

We presume that the images of you made on the website are indeed made with this shutter? If so, then it appears to do something correctly.... (Ron please confirm)

Ron -- so make one with a 5 1/2 inch hole, and we'll mount it on a coated Cooke Series VIa soft focus 460mm Knuckler (weighs 10+ pounds and barely fits on a 171x171 arca swiss board...the weight of this lens alone will destroy the front of most modern view cameras...)....lets see what the shutter can do.

[Ron Lee]

The photos posted in reference to the item being discussed ( said not to mention it again) are not manipulated, but actual results of the item being discussed here on this forum. I was about to loose face in this forum and go else where with my idea. So glad to see there are some that can see the need. I should have been more specific as to the type of lens this item was to target, though I did list brass lens and barrel lens. Are you serious about a 5.5 lens size, or just yanking my chain?
In the second week of Oct I will be at Natural Bridge shooting with my item and a variety of brass lens. I really like the tone these lenses produce. This year should be a great year here in Ky for Fall foliage because of all the rain that we have been getting. Sub soil moisture should carry through until late Oct with no additional rain. I live about an hour away and hope to get a group together for a two day outing.

[Don7x17]

The photos posted in reference to the item being discussed ( said not to mention it again) are not manipulated, but actual results of the item being discussed here on this forum. I was about to loose face in this forum and go else where with my idea. So glad to see there are some that can see the need. I should have been more specific as to the type of lens this item was to target, though I did list brass lens and barrel lens. Are you serious about a 5.5 lens size, or just yanking my chain?
In the second week of Oct I will be at Natural Bridge shooting with my item and a variety of brass lens. I really like the tone these lenses produce. This year should be a great year here in Ky for Fall foliage because of all the rain that we have been getting. Sub soil moisture should carry through until late Oct with no additional rain. I live about an hour away and hope to get a group together for a two day outing.

Quite serious about the Cooke. Jim Galli can confirm. And its coated circa 1956. A real brass beauty.
Several other large Petzvals in the collection have 4.5 inch element.

[Ron Lee]

"Ron -- so make one with a 5 1/2 inch hole, and we'll mount it on a coated Cooke Series VIa soft focus 460mm Knuckler (weighs 10+ pounds and barely fits on a 171x171 arca swiss board...the weight of this lens alone will destroy the front of most modern view cameras...)....lets see what the shutter can do."
Don could you email me a photo of this camera and lens along with its measurements and I will see what I can do. rtincher@hotmail.com

[Ron Lee]

Someone wanted to know about free fall guillotine shutter speeds. Here is the formula;
D=Vi*T+1/2*A*T^2
According to this formula a shutter falling 2.5" from a rest state has a velocity of 2.49mph or 3.652' feet per second. In 1/30 of a second will travel 1.45" inches. Great for a lens of this diameter for a true 1/30 setting.
A shutter falling 5" with travel 2.06" in 1/30 of a second, will cover 41% of a 5" lens. This will delay the time and by adjusting the shutter setting 1 &1/3 stops the correct settings can be acquired. This is what is accomplished if someone wants to build a shutter for different sizes of lens. On lens from 1.5" to say 2.5" (glass size) there would be very small correction needed to get a good printable negative. Hope this is of some benefit to at least a few interested members here.

[GSX4]

Ron, I am curious about this shutter even with all the ballyhoo it's created. I am interested in how you make the adjustments to get the speeds you say can be created?

[GPS]

Someone wanted to know about free fall guillotine shutter speeds. Here is the formula;
D=Vi*T+1/2*A*T^2
According to this formula a shutter falling 2.5" from a rest state has a velocity of 2.49mph or 3.652' feet per second. In 1/30 of a second will travel 1.45" inches. Great for a lens of this diameter for a true 1/30 setting.
A shutter falling 5" with travel 2.06" in 1/30 of a second, will cover 41% of a 5" lens. This will delay the time and by adjusting the shutter setting 1 &1/3 stops the correct settings can be acquired. This is what is accomplished if someone wants to build a shutter for different sizes of lens. On lens from 1.5" to say 2.5" (glass size) there would be very small correction needed to get a good printable negative. Hope this is of some benefit to at least a few interested members here.

A formula for free fall? But your shutter is not a case of free fall... It has friction not constant but changing with front standard tilt, among many other influences. Those who wanted to know about the shutter and know physics must have a clear idea by now about your claims...

[Don7x17]

Ron, I am curious about this shutter even with all the ballyhoo it's created. I am interested in how you make the adjustments to get the speeds you say can be created?

Ron - do you have an adjustable slit in the shutter?

[Ron Lee]

Ron, I am curious about this shutter even with all the ballyhoo it's created. I am interested in how you make the adjustments to get the speeds you say can be created?

Andrew; The adjustments are made by increasing or decreasing the size of the slit. Thanks for asking.