How to create a shutter

[glennfromwy]

I have a great old Voigtlander barrel lens I gotfrom Ole that I made a shutter for. It's a simple drop shutter with about a 5/16" slit. I made it out of a couple of broken dark slides. One piece for the rear, with a hole to fit the front of the lens. I glued a 1/4" piece of PVC pipe, sized to slip snugly on the lens, to this rear piece. Two narrow pieces of slide material, glued one on each side of the rear piece. The front piece is the same as the back piece, but plain, glued to the two side pieces. You should now have a thing that will fit on the front of your lens, with a hole in it for the lens to look though. Now, for the slide - it needs to be longer than the other part. Cut it to the width between the side pieces, so it will slide down inside the other parts. It will be kind of snug. You need to sand the slide to get it to slip freely through the space. A coat of paste wax helps make it nice and smooth to use. The size of the slit you cut in the slide will largely determine the shutter speed, as you drop the slide. With my shutter arrangement on my 8X10, I can easily get a pretty consistent 1/25, and 1/50 can be done. I hope I make sense with this. I'm not that good at explaining it. I can email a picture if you leave me a PM with your address. Jim Galli has used two old dark slides for a shutter, just flopping them past the lens, with pretty good results. What I don't know is how well any of this will work for a hand held camera. Good luck.

 

[Murray@uptowngallery]

I talked to a guy who worked at ReCon Optical decades ago and asked if the big leaf shutters (like on the 24" Aero Ektar for example) didn't cause objecionable vibration due to careful damping and low mass compared to the rest of the lens assembly.

He said yes, but the smart part was keeping the blades quiet during motion and allowing the vibration to happen at the start (damped quickly before fully opened), and they could vibrate all they wanted after the leaves closed (doesn't affect the exposure then!),

If you've seen/heard a 4" or larger shutter at 1/400 you'd realize how nice and safe it is between thick layers of glass lens. I wouldn't want to get near those blades if they were behind the lens. I think the spring wire for my 24" Aero-Ektar shutter is approximately 1/16" thick wire (I took it out anyway).

See Jim Galli's darkslide shutter - find a post of his, then goto his website. Not elegant but very effective...uh, I guess not for hand held use..you already have hands on the camera.

Take a look at a Polaroid 95B, 150, 160, 800 type camera - again, not as fast or large as you want, but a pretty slick design that still works on 50 year old cameras. Only thing that goes badly wrong on them is the foam rubber damper at the magnetic shutter catch. Oh, the other thing that goes wrong is me taking cock/release springs out & getting confused. Anyone else should be able to handle that.

My 50+ year old Compurs, Rapaxes, & Kodaks are in cahoots with the camera repair people.

Along the lines of Nicolai_'s suggestion of a Holga-style rotary aperture shutter, I started & was distracted away from a Lazy Susan bearing shutter. Forgotten, but not gone. Hmm, not good for handheld either.

Hard drive head actuator, batteries and a timer. typ. 17 ohm coil, needs 6-12 volts to break away from the magnetic catch (or get rid of it). Forget long exposures - tends to drain batteries.

 

[nicolai]

If you want to go that way and do long exposures, you could have two actuators, one to open, and one to close.

 

[Dan Fromm]

If you want to go that way and do long exposures, you could have two actuators, one to open, and one to close.

Its been done. Williamson/AGI F135. Two opposing solenoids, one extends to whack the shutter open, the other extends to whack the shutter closed. But quite a small shutter.

 

[nicolai]

Yeah, in this case, I think "been done" is good, because that probably means it works.

 

[Murray@uptowngallery]

I met a guy from Colorado through F295, he stopped in the gallery one weekend about a year ago. He works for a company that makes LCD shutters up to I think 45mm aperture, and I swear he said it'll do 1 millisecond (1/000 for you analog folks).

I should have asked how much they were but didn't.

 

[Falkenberg]

do You have a link to his company ?

 

[nicolai]

Holy crap! I'd love a link, too!

 

[3Dfan]

For info on how packard shutters work - http://www.electricedge.com/greymatter/archives/00006060.htm

 

[Murray@uptowngallery]

I will try to find his business card. It was sitting on a work table for months. The company is in Colorado. His name is Greg.

I'll see if I can produce more information short of undergoing hypnotism...oh, wait...already there...

^%@W- not in the Rolodex...I'll do some research.
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http://www.freepatentsonline.com/6677999.html

This says HP is associated with it, and both of the assignees had a Colorado address. Greg didn't say he worked for HP, but he might have mentioned HP for some reason in our conversation...

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I have one other lead I bookmarked. I'll release it to y'all once I have received correspondence from the company. I promise.
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[Murray@uptowngallery]

If I still have the business card, it's in one or more boxes of stacks of papers that periodically get moved into a box. It may turn up IF I find the boxes.

 

[Murray@uptowngallery]

OK, we have all heard of such specialized things as LC(D) shutters, in some form, for a particular situation. I read it myself in a 4 or 5 volume Kingslake Optical Engineering library.

I contacted a company I found on the web and they responded that their particular technology was not really suitable because of angle of view issues. Following is a Tech_Support FAQ about this.

http://www.liquidcrystaltechnologies.com/tech_support/LCDShutterConsiderations.htm

There remains a Holy Grail somewhere, perhaps that patent from Colorado, at unknown cost for unknown applications.

If I haven't mentioned it yet, I'm looking at Scotch Yokes as a sinusoidal rotary to linear motion conversion for a large (I say large, like Foghorn Leghorn says large) lens where the mass will probably help resist vibration.

 

[jimgalli]

Here's a link to the (there was a url link here which no longer exists) Not exactly what you're after but the idea of 2 dark slides making the same motion on an axis as a cine shutter is sound. For electronics there are thousands of old HP and Tektronics oscilloscope cameras that go begging on ebay for 9.99. Many of them have a grand little electronic circuit with times from 1 sec to 1/125 just like any camera that runs on 6 double a batteries. You could pull one apart and use the circuit and selector switch and perhaps the shutter parts. Look at the C51, C5 Tektronics and any of the old square HP versions.

 

[Murray@uptowngallery]

Here it is....

Dead Link Removed

The 45 mm clear diameter one is about $1500 + $300 for driving electronics. Max. speed is 70 microseconds with a complex drive waveform. 300 microseconds for single state change using a simpler bipolar +/-5 V drive.

I didn't ask how much the smaller ones were.

I think it's ferroelectric liquid crystal, and has limits on contrast ratio (30 dB 1000:1 I think).


Not for everyone or everything.

Don't buy one based on my description alone - read the prospectus, etc.

 

[Joe VanCleave]

Back to the guillotine shutter, you could make a falling blade shutter, or perhaps better would be a horizontally travelling spring loaded shutter, powered by a spring so that the falling speed is not dependant on camera orientation. Then have an adjustable slit size, which would be a second, smaller blade, mounted to the 1st, with markings for calibrated speeds. The main blade has the widest slit opening; the secondary blade is positioned at preset locations to make the effective slit narrower, for faster exposure times.

You would also need a second shutter blind, with no shutter opening, to keep the film from being re-exposed as you recock the main shutter back to its ready position. Or, have the secondary blade of the shutter itself do this function: connect a shutter lever or button to the adjustable shutter blade of the main shutter itself. After it's been fired, when you operate the cocking lever it pulls on the adjustable blade first, which moves it to cover up the shutter slot completely before the shutter begins to move to the loaded position. After it's recocked and latched ready to fire, relaxing the cocking lever permits the secondary blade to be pulled, via a spring, back to its preset open speed position, and the shutter is ready to go.

Sounds more complicated to explain than a simple illustration would provide. Could be made from simple sheet brass and hardware.

~Joe

 

[pauliej]

Here is a link to Flickr, where this guy has a variety of homemade cameras with various shutter designs. Mostly pinhole, I think you may find something that could work for you. I hope this helps you.

http://www.flickr.com/photos/michael-pastur/542879141/in/set-72157600306662355/

Paul