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Thread: How It Works?

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    aaronmichael's Avatar
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    How It Works?

    I was telling some of my friends about pinhole photography the other day, showing them my plastic 35mm film canister pinhole cameras and some photos I took with them. They all asked the question "Well how does that work?" I told them that all the light from outside the pinhole travels towards the pinhole and then spreads back out after passing through the pinhole, therefore creating the image. Then one of them said "But how does that work?" and I was at a loss for words - haha. So is there a more complicated science behind it or is it really as simple as what I told my friends? That's the only way I knew how to explain it. How have you explained pinhole photography to people that didn't know about it?

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    bobwysiwyg's Avatar
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    This is pretty straight forward. The only thing I might add is the light doesn't 'spread' so much as the light point will appear 'opposite' positionally within the camera. At least that's my explanation.

    http://www.howstuffworks.com/question131.htm
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    Poisson Du Jour's Avatar
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    The method of pinhole cameras goes back a long, long way to the very basic origins of image formation "caught in the box".

    The simplest "how it works" explanation is that light rays from the scene pass through the single (pinhole) point and project an inverted image on the opposite side of the box (onto film, or any photosensitive material enclosed).
    Our eyes, in bright light act in a similar way, as do modern cameras using quite small apertures. Pinholes don't have a mirror to flip the image right-way up, like the human brain does, or by which SLRs using mirror systems accomplish the same thing.

    In this month's National Geographic magazine is a fascinating spread on pinhole photography using a large format set up to project images onto walls in homes, on the ground in floorless tents and a demonstration of the simplest visual explanation of image formation using a light globe to visibly project an inverted image of it inside an open (no photosensitive material) cardboard box pinhole "camera". It's well worth a look for the innovative twist on an old method.
    .::Gary Rowan Higgins

    A comfort zone is a wonderful place. But nothing ever grows there.
    —Anon.






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    I tell people that pinhole cameras/photography acts the same as any other photograph. The only difference is pinhole cameras do not have a lens, which means the photograph has a softer effect.
    Ric Johnson
    Proud member of the League of Upper Midwest Pinholers & f295

    "I think, therefore, I photograph."

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    puptent's Avatar
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    Quote Originally Posted by bobwysiwyg View Post
    This is pretty straight forward. The only thing I might add is the light doesn't 'spread' so much as the light point will appear 'opposite' positionally within the camera. At least that's my explanation.

    http://www.howstuffworks.com/question131.htm
    Originally known as Camera Obscura. A room, or tent, with a pinhole aperture that projects an image on the backwall or an easel for tracing by an artist or draftsman inside a darkened room. The diameter of the pin hole is related to the focal length, or distance between the pinhole and the capturing surface; the wall, a piece of film, photo paper, whatever. If the diameter of the aperture is too large, like a window, there will not be the inversion and focusing of the image. I think that theoretically, there is an optimum focal length for each pinhloe aperture that will focus perfectly, or am I wrong about that? So, in theory, if the focal length was long enough wouldn't an aperture as large as a window focus an image?
    "We often think that when we have completed our study of one we know all about two, because 'two' is 'one and one'. We forget that we have still to make a study of 'and'."
    -A. S. Eddington

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    puptent's Avatar
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    Oh, and BTW, the mirror in an SLR serves only to re-direct the light from the lens to the eyepiece, it swings away just before the shutter is opened, and the image captured on the film will be whatever is fucused by the lens. And it's true that the image on the back of your eye is inverted, all babies see everything upside down until the brain learns how to compensate.
    "We often think that when we have completed our study of one we know all about two, because 'two' is 'one and one'. We forget that we have still to make a study of 'and'."
    -A. S. Eddington

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    bobwysiwyg's Avatar
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    all babies see everything upside down until the brain learns how to compensate.
    How do 'they' know that?
    WYSIWYG - At least that's my goal.

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    puptent's Avatar
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    Hi wysiwig (love the handle!) the cornea is a lens, and it has physical properties the same as a lens, so, what's on the back of your eyeball is the inverted image of what ever you are looking at. Your brain actually learns how to rotate the image so that it makes sense. =)
    "We often think that when we have completed our study of one we know all about two, because 'two' is 'one and one'. We forget that we have still to make a study of 'and'."
    -A. S. Eddington

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    aaronmichael's Avatar
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    I'm aware of the focal length, diameter of pinhole, apertures,...etc. I was just having a hard time trying to explain it and how it works. I suppose it is as simple as a beam of light passing through the hole and ending up projected on the other side. I think I'll have to use the flashlight example next time I try to explain.

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    bobwysiwyg's Avatar
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    What I really meant, but didn't phrase correctly is, how do they know the baby doesn't see it the same way we do right from the start? Did they ask them?
    WYSIWYG - At least that's my goal.

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