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  1. #11
    Struan Gray's Avatar
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    Have you tried mounting the Sinar shutter backwards where the lensboard would go? That would allow you go get on with taking pictures.

  2. #12
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    Taking the Sinar shutter apart

    I was thinking about taking the Sinar shutter apart. I want to see if I somehow can use the shutter and discard the aperture thingy. If this is possible I could mount it inside/behind the lens. Since the camera will be easy to open it would not be hard to adjust the shutter speed. My design have to be finnished by nov. 1. since I have a date with the 3D printer and will have to make a more or less final print. I am thinking about making the design even more modular than I had started out with. This way I can add a small "spacer" behind the lensboard where I can make a gravity/cardboard shutter.

  3. #13
    Struan Gray's Avatar
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    The Sinar shutters have a reputation for being difficult to put back together again after disassembly. Unless your university really does not want it any more I would advise against taking it to bits.

    How big is your lens, and what sort of angle of view is it intended to give? If it's not too big, and not too wide, it would be simple to build an extension box around the lens and mount the shutter on that. I have seen a couple of vintage Swedish cameras that did this - one had the finesse that the sides of the extension box were sliding louvres so you could access the aperture control on the lens.

  4. #14
    Falkenberg's Avatar
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    It is a Schneieder-Kreuznach Symmar-S 5.6/300. All the parts are mine and I can do with them as I want, but I want to keep the things in working order if possible. The camera I am building is a no movement 8x10" "point and shoot" portrait camera.

  5. #15

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    Quote Originally Posted by Falkenberg View Post
    My camera project seems to consist of problems to be solved. The Lens I have got is without a shutter. The Lens is mounted in a Sinar board. It has Aperture setting, but no shutter. Now I am thinking about how to make a shutter for my camera.

    Has anybody created a shutter ? Maybe an electronic one.

    Any input will be appreciated.

    Best regards
    Mikkel
    Google "packard shutter". Or you can use a black piece of paper. Simply put the paper over the lens, remove the darkslide from your film holder, then move the paper. I've done 1/4 second or so exposures reasonably well this way.
    The universe is a haunted house. -Coil
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  6. #16

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    Quote Originally Posted by Falkenberg View Post
    I like this idea. A sliding piece of paper as a shutter. Not exactly electronic, but very cool. Using gravity, it should not be to difficult to calculate the size of the opening in the paper. Would it be best o place the shutter at the lens end or at the film end.

    Any input on foormulas for calculating the opening in the papers would be highly appreciated.
    You could also look at the simple but somewhat elegant shutter design of the lowly Holga. It's a spring-loaded rotating wheel. When you push down the shutter lever, it pushes up on a spring connected to a tab on the wheel. The wheel has some kind of detent, but once the spring is compressed to a certain point the wheel is pushed out of the detent due to the force and it rotates quickly. The wheel has a hole in it, and the plate the wheel is mounted to also has a hole in it. When the wheel rotates, the two holes align briefly and an exposure is made. I think somehow the wheel rotates 360 degrees to get reset but I don't have it handy to see how it works. Obviously it can't just turn back past the hole or you'd get a double exposure. You could probably figure out how to get a bulb setting into this design.

    There's a closeup picture of the shutter on this page in the part on pinhole modification (caption: "step 3"). It's flash embedded so I can't link the image directly. Maybe you can trace its function by carefully looking at this static picture; the safety-pin style spring is what gets compressed initially when you hit the shutter lever (right side of image in the closeup).

    Wait, found the plain image:


    Comes from this page:

    http://www.squarefrog.co.uk/holga-hacks-pinholga.html
    The universe is a haunted house. -Coil
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  7. #17
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    Quote Originally Posted by Dan Fromm View Post
    BTW, cine camera sector shutters just go round and round, they don't start and stop.
    Yeah, but they do have adjustable angles, which when combined with a still camera rotary shutter that does stop could be cheap, easy, and versatile.

  8. #18
    Struan Gray's Avatar
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    Quote Originally Posted by Falkenberg View Post
    It is a Schneieder-Kreuznach Symmar-S 5.6/300. All the parts are mine and I can do with them as I want, but I want to keep the things in working order if possible. The camera I am building is a no movement 8x10" "point and shoot" portrait camera.
    With a lens that big I think my trick of reversing the Sinar shutter isn't going to be ideal - the lens will lever the shutter downwards, unlike in the 'proper' Sinar arrangement where the lens and shutter are attached to different sides of the standard/format frame.

    In any case, the Sinar shutter has a top speed of 1/60th, and that's also less then ideal with a 300 mm lens if you're going to hand-hold the camera. Even transferring the lens cells to a Copal 3 will only give you 1/125. A lot depends on what sort of photograph you want to take, but I would want something faster for a point and shoot. This rules out most homemade shutters too.

    If you have the time, you might consider looking for a smaller lens which fits in a Copal 1, or which can be placed in front of or behind the cheap shutters from oscilloscope cameras.

  9. #19

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    Quote Originally Posted by nicolai View Post
    Yeah, but they do have adjustable angles, which when combined with a still camera rotary shutter that does stop could be cheap, easy, and versatile.
    Depends on the cine camera. The vast majority of S8 cameras have fixed shutter angle.

    The reason I brought up starting and stopping is that one of the problems of making a shutter for still cameras that works well is managing acceleration and deceleration. Many are the problems, weak are the materials, ... Cine cameras typically lose a frame on starting and another on stopping. A partial exception is the 8/8 Leicina, which stops the shutter by sticking a pawl into a slot in the main shaft. Bang! and its stopped.

  10. #20
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    True, not all have them (though a lot of 16mm and AFAIK almost all 35mm do). While I wouldn't claim that Holga-style still rotary shutters are absolutely stable, they're surprisingly far into "not bad" territory. I had a Holga shutter tested, and while it certainly wasn't as accurate as an electromagnetic shutter, I was surprised by its consistency (I don't remember the exact tolerance as it was a few years ago, but it was around the same as a spring-driven curtain shutter).

    For a crappy shutter, the Holga's isn't bad. The hole is at the end of disc travel, where it's more likely to be at maximum and consistent speed. If you had an adjustable hole, you probably wouldn't be able to simply say that half the size will yield exactly half the exposure time because of acceleration, as you mentioned. But you can build a shutter tester to interface with a computer sound card (or build one with an Arduino) very cheaply, and if the gap is continuously variable, it should be fairly trivial to figure out the correct spacings by trial and error.

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