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Thread: 4x5 pinhole

  1. #11
    Lee L's Avatar
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    In the US, Krylon Ultra Flat Black spray paint is a good place to start for paint. You can also find black flocked self-adhesive paper and felt at hobby stores. Either way will probably work very well for killing internal reflections.

    Also found the angle of view data, although stated differently by Renner. The image diameter on a flat surface (non-curved film or paper) is approximately 3.5 times the focal length with a good pinhole. One inch of focal length gives you a 3.5 inch diameter circle, so 1.85 inches or 47mm of focal length should give you corner to corner coverage on 4x5.

    Lee

  2. #12
    Donald Qualls's Avatar
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    Hmm. I've got hand-made pinholes in a pair of gum-tin cameras that are .006", varying by about .0003" between them. Yes, that's half a stop difference, but it's as close as I'm going to get without spending far too much time on them.

    And FWIW, I have pinhole cameras that cover the film reasonably well with better than 115 degree FOV; a pinhole is capable of about 140 degrees if you use some means like a curved film to overcome light fall-off.

  3. #13
    Jersey Vic's Avatar
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    Ultrawide

    Quote Originally Posted by David A. Goldfarb
    That sounds interesting. How wide can you go with a pinhole? Theoretically as wide as you want, I suppose, but out of curiosity, how wide is practical? Could you make a usable photo with pinhole, say, 10mm or 15mm from the film on 4x5" or is the falloff too great to see anything in the corners?
    The camera I made is a 37.5mm and that length works pretty well in terms of vignetting so long as conditions are moderately bright. I imagine at 10-15mm you won't be able to cover very much of the film plane. The real problem with the 37 is finding appropriate subjects. You need to be practically on top of what youre shooting to fill any significant amount of the frame . I'll scan a couple of images when i return from "upstate".
    Cheers

  4. #14
    David A. Goldfarb's Avatar
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    Quote Originally Posted by Jersey Vic
    I'll scan a couple of images when i return from "upstate".
    Thanks, I'd be interested to see them.
    flickr--http://www.flickr.com/photos/davidagoldfarb/
    Photography (not as up to date as the flickr site)--http://www.davidagoldfarb.com/photo
    Academic (Slavic and Comparative Literature)--http://www.davidagoldfarb.com

  5. #15
    htmlguru4242's Avatar
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    Yes, definetely do scan those images; they'd be interesting to see.

    I was thinking of using Krylon Flat Black, as its easy to find, and, being a spray paint, covers quite nicely.

  6. #16

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    another simple pinhole camera design is made by 2 boxes that fit inside eachother ( like sheet film boxes ) ... one has a hole in the front ( for the pinhole ) the other has a handle on it to aid in pulling it out, or pushing it in. i have a 8x10 pinhole like that, and it works great. you can also use a shoe-box.

    it doesn't have to be made of wood, it can be made of black cardboard/foamcore/matboard or pretty much anything ...

    you can multilpy whatever focal length you want to use by "3" to find out the image circle ... when i was making a 12x20 pinhole that was the number given to me so i would avoid "bowing" my film ...

    good luck!

    -john

  7. #17

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    Here is a link for a 4x5 pinhole camera that can hold a 4x5 film holder. The fit is a bit tight for a polaroid back, but I have used them as well.

    I have also included plans for a pinhole camera you can build out of form core.
    Attached Files

  8. #18

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    I've an old Graphic that I would love to use as a pinhole camera. Is focusing done by measurement only?

  9. #19
    Lee L's Avatar
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    Quote Originally Posted by waynecrider
    I've an old Graphic that I would love to use as a pinhole camera. Is focusing done by measurement only?
    You don't really focus a pinhole as you would a lens. You just set it at some distance from the film, which is your focal length. All things are equally sharp from near to far, but none are perfectly sharp. You can get your focal length by measuring, and you can change it with the focusing rack. You also can measure the size of the pinhole, and a given pinhole can serve for a range of focal lengths, dependent on your tolerance for unsharpness. Focal length divided by pinhole diameter gives your f-stop (when measured in like units).

    An old Graphic makes a great pinhole camera.

    Lee

  10. #20
    wildbill's Avatar
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    All this talk got me going and now i see someone else tried foam cor as well. I had some 1/2" black foam cor and some 1/4 as well that i threw together in about 2.5 hours tonight. I shot a couple polaroids for the hell of it and it works. I used the dimensions of my shenhao back for a reference, it's 6x6 roughly. The camera has a 75mm focal length.
    Attached Thumbnails Attached Thumbnails pinhole-back-empty.jpg   pinhole-side.jpg   pinhole-front.jpg  
    www.vinnywalsh.com

    I know what I want but I just don't know how to go about gettin' it.-Hendrix

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