180 degree flat fim camera milestone

Discussion in 'Pinhole Photography' started by autodafe, Dec 8, 2008.

  1. autodafe

    autodafe Member

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    An idea of one-hole pinhole camera. Flat film and up to 180 degree of view.

    http://pieknedni.blogspot.com/

    A milestone for me. I made this ~4 years ago, never made a photo with such designed camera, I've just seen an image on paper.

    Or maybe someone invented this some time ago and I did't knew it?

    What do you think about it?

    Cheers,
    Luke
     
  2. q_x

    q_x Member

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    Excuse me, this should be posted from this account, not Autodafe's.
    Sharing PC is not always good.
    Sorry,
    Cheers,
    Luke
     
  3. Ian Grant

    Ian Grant Subscriber

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    Well now it seems there's 3 of you :D

    The Hypergon with fan uses a similar principle, but needs part of the exposure to be made without the fan.

    Ian
     
  4. q_x

    q_x Member

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    Oh, no!
    But thanks for pointing weakness :smile:
    My idea was not to filter-out the light from the middle (wich is much easyier), but changing geometry of pinhole:
    from simple hole laying in 0 deg. angle to film's surface
    to circular (rectangular or whatever) slit *perpendicular (90 deg angle)* to film's surface.

    I'll edit the blog entry to make it clearer.

    Cheers
     
  5. q_x

    q_x Member

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    Ok, I've added some attachments, also posted on blog.
    Hope it is clear: close to the pinhole (slit?) only very small ammount of light gets through. Far away from pinhole the ammount of light is much bigger, this helps to get rid of falloff wit wide angle cameras. Getting rid of black spot in the middle should be easy - by placing some tube with additional pinhole in the middle of the circle. But it needs to be researched.
     

    Attached Files:

  6. q_x

    q_x Member

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  7. Jim Jones

    Jim Jones Subscriber

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    For best sharpness the pinhole in your system should be very small. Perhaps the best way to position a tiny dot centered at a small distance behind a small pinhole is to attach the dot to thin glass (like a microscope slide or cover) and center that beneath the pinhole. When the pinhole is exactly centered over the dot, it could be cemented in place.

    Another idea for a flat film extreme wide angle pinhole is on page six of http://inside.mines.edu/~mmyoung/PHCamera.pdf. There will be much falloff near the edges.
     
  8. bowzart

    bowzart Member

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    It is possible to etch a pinhole in an old mirror with the backing removed. New mirrors aren't silvered, necessarily, like the old ones were. Old mirrors were made of a thin film of silver deposited on glass. The pinhole can be made with a lith film exposed to a circle, the size calculated by the object to image formulas you can find in the books. Go to Radio Shack in the US or whoever sells printed circuit supplies where you are. Get some photoresist and whatever is used for developing it. Expose using the lith negative (or positive, depending on the resist you are using) to the mirror with UV light, and develop. Often the developer is simply NaOH with positive resists. The hole can be etched out with farmer's reducer. A good source of front surface mirrors (advantage: there is no backing to remove) is salvage from scanners. I think the good ones are silvered; not sure, but if they are aluminized you would need a negative working resist that develops in UGLY chemicals, and etch with NaOH. Then, you can paste a circle to the other side of the glass.

    Will this work? I doubt it. It certainly will NOT be 180°. Will it be fun? I suspect so. I believe it is not possible to produce 180° using a single hole. It is sort of like the "perpetual motion machine", IMHO.
     
  9. q_x

    q_x Member

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    I see you get it :smile:

    Guys, thanks you're here :smile:
    Yes, you are right. Attaching pinhole is the hardest part. I've done it badly, it ruined my photo once. So I did it again - still it is not good :D
    I've been using a knife or a needle (from the syringe, with top cutted in perpendicular manner) to make the hole (and the "cap" in the same time).
    Using glass... Well, only glass I can imagine to be used is the thin cover used with microscope preps. And the only method to make pinhole is to do this with pigment-like emulsion on the "cap" side.
    I'm making solarigraphy now (with big bad hole, so I will have both normal pihnole image and "enchanced" one overlapping eachother and both wery blurry).
    Hope to get it out after Christmas and see what it will be there.
    I'll make a report ASAP.
    Cheers, thanks,
    Luke
     
  10. q_x

    q_x Member

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    bowzart, I'm getting 150-160 degrees right now. With camera (build within 2 hrs) totally screwed up in every possible part. 180 without distorsion and one hole is speculative maximum. Imaginable, but never to be built. Unless something else will cross my mind.
     
  11. bowzart

    bowzart Member

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    Well, good luck. My understanding is that about 150° is pretty much the limit and even that is questionably practical.

    My thought is that if you view a circle from the front dead center, it appears to be a circle. As you tilt it so you are no longer looking at it on axis, it becomes less circular, and the more you tilt it the greater the ratio of the length of the ellipse to its width becomes. As this becomes very extreme, the ellipse becomes more like a straight line to the eye and less like a two dimensional shape. At 180°, you'd be looking at the edge of the plane the circle is inscribed upon, and you wouldn't even see the circle at all!!

    Additionally, there are two other factors in play here. First, as the view from points on the image plane get farther from the axis, the difference between the axial circle and the off - axial ellipse represents "lost" light. The hole is actually getting smaller (in its area) in relation to the image plane. And of course, the distance from pinhole to film becomes progressively much greater with that extreme geometry. Remember that the intensity of the light varies inversely to the square of the distance from the source. So the light fall off will be extreme, and probably, regardless of the amazing feat of getting a great wide angle, would be impractical.

    Unless you get the making of the pinhole down to where the material is extremely thin, you are making a tube, which further limits your ability to achieve a wide angle. One reason I like the idea of using a front surface mirror is that the material deposited on the surface can be far thinner than any piece of metal you could possibly use.
     
  12. q_x

    q_x Member

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    Yes, of course you're right. I'm trying 160 degrees camera now and 150 deg is maximum.
    As I said - this is a milestone in construction of wide-angled pinhole cameras. Not half as brilliant, as the others. And it needs polishing. It needs mathematic instrument (or software) I don't have, to make it better. I'm (probably) a nerdy artist, not artistic nerd.
    However - I've checked the maths - it seems this construction should work. As far as 1) the plate is very thin and 2) the cap is very close to the pinhole :smile:.
    With all my heart in this project, I will not put any glass between the film and rest of the world. This is the dogma for me.
    But others can do it :wink:

    As I said - I will post my first solarigraphy with some comments after Christmas Eve.

    Cheers,
    Luke