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Thread: New article: guillotine shutters

  1. #31
    joseph
    Join Date
    Jan 2007
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    New York
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    1,400

    Re: New article: guillotine shutters

    Sounds like you've been having problems with the sliding flap of your meds dispenser-

  2. #32

    Join Date
    Nov 2008
    Location
    Atlanta, GA
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    596

    Re: New article: guillotine shutters

    Solution to tilt was previously covered: The speed the shutter curtain travels is going to vary with the angle of tilt somewhere on the order of R * cos theta for a tilt of theta from the vertical for your typical rate of travel R. -- probably only good for small thetas.

  3. #33
    Lascassas, TN
    Join Date
    Jan 2006
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    Lascassas TN
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    196

    Re: New article: guillotine shutters

    Like I said in this article, this provides a quick way to add a shutter to a barrel lens. I can play with different glass without the expense of even a Packard Shutter. I am not a “Magic Bullet chaser”. If low tech works, it saves me money; I can buy more film.

    Material selection is the user’s choice. I have tried both wood and metal blades. The weight of the blade is not a factor in shutter speed. I use what is at hand.

    The channel width was set to allow the blade to free fall. This reduced friction to a minimum. With wood, I coat both the blade and slot with cabinet drawer slide lubrication or rub in paraffin wax.

    The release technique used to drop the blade induces the most variation. I practice a few times before I pull the dark slide. Someday I will add a release. My shutters are set up with the blade in free fall. Weight of the blade is not an issue.

    Since most of my large format work is landscapes and portraits, the 15 degree from horizontal limitation works for me.

    Have fun.
    Bill Kumpf

  4. #34

    Join Date
    Jan 2010
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    55

    Re: New article: guillotine shutters

    I think it is important to re-visit these other methods for exposure control. I am somewhat sure "modern" shutters are more accurate. But if you want to put a shutter on either an antique lens or a lens you build on your own, this is a way to go.

  5. #35

    Join Date
    Apr 2009
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    Seattle area, WA
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    863

    Re: New article: guillotine shutters

    Quote Originally Posted by jp498 View Post
    I was pleasantly surprised at how consistent the testing revealed the shutter to be. That's excellent. However, I suspect as soon as your rubber band rotted out in a couple months
    Get Rubber bands designed for RC planes. They aren't going to rot out for a long time- they are UV,chemical resistant etc etc.. much better then the rubber bands you get off your morning paper.

  6. #36
    hacker extraordinaire
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    May 2009
    Location
    North Carolina
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    1,329

    Re: New article: guillotine shutters

    Na, RC plane rubber bands disintegrate just as fast as any other. Probably faster, because they seem to have a high percentage of natural latex in them for stretchyness. I fly RC planes and the rubber bands are semi-disposable. Some use new ones every time.
    Science is what we understand well enough to explain to a computer. Art is everything else we do.
    --A=B by Petkovšek et. al.

  7. #37
    Mike Anderson's Avatar
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    Jan 2010
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    San Diego
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    Re: New article: guillotine shutters

    Quote Originally Posted by GPS View Post
    ... This Holy Grail of amateur inventors is still full of potential. Nylon roll bearings, modern mineral oils could give a new life to the guillotine shutters...
    I think an air bearing might work here. The actual shutter (the falling part) could be simple laminated cardboard, like playing cards, cheap and when they get frayed or warped you simple buy a new deck. Each card would have tables printed on them to specify their exposure time for each focal length/tilt combination. Once you've dialed in your tilt you simply pick the card that gives you the desired exposure for the focal length you're using. The shutter release simply releases the card so there's very little vibration.

    The main drawback is that you need an assistant with good lungs.

    ...Mike

  8. #38

    Join Date
    Jun 2005
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    2,480

    Re: New article: guillotine shutters

    Two small rubber wheels running silently on batteries, in a narrow slit (like a credit card entrance). As soon as a shutter slide touches them they swallow it running it at a constant speed, in all camera positions. Each speed has its own slide card (shutter speeds written on them with big letters and the actual precision measured + -0.0001s)... hmm, hmm, the Holy Grail at its best..?

  9. #39

    Join Date
    Jul 1999
    Location
    Paris suburbs, France
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    124

    Re: New article: guillotine shutters

    Quote Originally Posted by GPS View Post
    the Holy Grail at its best..?
    As soon as having seen the real thing, I will consider to parish. Possibly with a free opening 1,5x larger than a credit card and vibrations at the level of a Copal.

  10. #40

    Join Date
    Jun 2005
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    2,480

    Re: New article: guillotine shutters

    Quote Originally Posted by Dominique Cesari View Post
    As soon as having seen the real thing, I will consider to parish. Possibly with a free opening 1,5x larger than a credit card and vibrations at the level of a Copal.
    ?? If only you won't perish while doing so, it's all fine...

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