Fresnel Lens As Imaging Lens

Discussion in 'Alternative Processes' started by holmburgers, Apr 5, 2011.

  1. holmburgers

    holmburgers Member

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    I bought a cheap page magnifier for the purpose of putting it on my GG.

    In the meantime however, I've been playing with it; holding it up to a wall opposite a bright light and observing its imaging abilities.

    The image it creates is wonky to say the least, but it's also quite interesting. It is also very bright!

    I'm wondering a couple things. First, what would the f/ stop be? Finding the focal length would be simple enough, but how much of the diamater should I consider as lending to the maximum aperture, if that makes sense.

    The other thing is whether or not creating a simple aperture/mask will increase the quality of the image. I'll experiment with this when I get home and see what the result is.

    At any rate, if you've got a fresnel lens, take it out and play with it. It might have some potential for interesting images.

    Anyone ever done this?
     
  2. Whiteymorange

    Whiteymorange Member

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    Never done it but, as an inveterate explorer into things that no one in his left mind would ever do, I say GO FOR IT! Try an educated guess on exposing a paper neg and adjust as you go. Paper isn't that costly and the process is simplified if you have a darkroom set up for printing.
     
  3. ic-racer

    ic-racer Member

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    Its just like a regular plano-convex lens, they just take out the middle bulky part :smile: . So the aperture is the diameter of the lens sheet.
     
  4. holmburgers

    holmburgers Member

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    Thanks guys. That makes it probably less than or very close to f/1. :blink:

    I have no idea about how to go about making a camera of this sort however. The shutter specifically. Some kind of crude, perhaps cardboard, focal-plane shutter might be the best bet.
     
  5. Andrew O'Neill

    Andrew O'Neill Subscriber

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    I did this a few years ago with a box camera that I made. Make yourself an apeture out of black construction paper. I made myself a set of three. Image quality improves with smaller apetures. Got some interesting images.
     
  6. holmburgers

    holmburgers Member

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    Hey Andrew, that's great. Got any examples easily accessible?

    I just made some paper apertures to fool around with. I wish I had a Graflex with the focal-plane shutter and I'd just make a lens-board out of a fresnel.
     
  7. tomalophicon

    tomalophicon Member

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    You shouldn't need a shutter with paper negatives. That sounds like fun, let us know how you go.