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Thread: Circular Image Pinhole Camera

  1. #11

    Circular Image Pinhole Camera

    Very nice, Peter.

    And that can should impress the big lens crowd, too.

  2. #12

    Circular Image Pinhole Camera

    Peter, thank you for sharing your camera building idea and the wonderful images. I especially like the last image posted. The toning and the round image really lend a 19th century feel to these.

    I was thinking that your camera looks as if it needs a rangefinder focusser on top, and a hand grip on the side!

    ~Joe

  3. #13

    Circular Image Pinhole Camera

    Actually, a couple of 10 pound barbells come in handy on windy days...

  4. #14
    500+ Posts earlj's Avatar
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    Circular Image Pinhole Camera

    Using the cosine^4 calculations, here are the angles off of perpendicular for whole stop light fall-off:
    1 stop - 32.7 degrees
    2 stops - 45 degrees
    3 stops - 53.5 degrees
    4 stops - 60 degrees
    5 stops - 65.1 degrees
    To get 5 stops light falloff at 4 inches off center, the pinhole to film distance needs to be 47.08 mm, or 1.85 inches. I calculated this by finding the tangent of 65.1 degrees, which is 2.157974571 and then dividing 4 inches by this number (tangent = opposite/adjacent).

    The cool thing about a circular image area is that you don't have to worry about the horizon being level . . .

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