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  1. #1

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    Brownie Hawkeye pinhole conversion question

    In an effort to participate in the upcoming Worldwide Pinhole Photography Day, I'm in the process of converting a Kodak Brownie Hawkeye Flash to a pinhole camera. It's essentially a very simple matter to replace the lens with a pinhole, but there are two potential locations for the pinhole - which one to choose is my question.

    For those unfamiliar with the Brownie Hawkeye, there is a flat glass plate located at the front of the camera to protect the shutter. Behind the shutter is the actual lens. The distance between the two is roughly half an inch, with the ~5mm aperture hole that is integral to the shutter in between. My plan was to place the pinhole where the lens was, but this means it will be behind the aperture in the shutter and about half an inch behind the front of the camera body. Would there be any reason to instead replace the glass plate on the the front of the camera body with the pinhole, and simply remove the lens? My concern was that doing the latter would result in serious vignetting, but I'm not sure if the former arrangement won't have problems of its own.

    According to information I've gotten from around the internet, the ideal pinhole size for this application is 0.015 inches. My plan was to use a drilled brass plate with a #79 (0.0145 inch) drill in a pin vice.

    I'm quite new to the whole pinhole photography thing, so any advice or suggestions you might have are very much appreciated. Thanks.
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  2. #2
    DWThomas's Avatar
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    Hmmm - it's possible locating the pinhole much of a distance from the aperture could result in vignetting -- maybe someone out here in cyber-photo land has actually done one and can chime in. Substituting a pinhole plate for the lens will result in a field of view similar to the lens version so that could mean everything will be happy. I know in some other pinhole stuff I've done where there was a relatively wide angle of view, it's amazing how easily vignetting reared its ugly head.

  3. #3

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    I've looked around the web for any examples of similar conversions without success. I'm hoping that the distances between the aperture and the pinhole plate will not interfere, but I can't find any specifics that would allow me to determine this prior to loading film and finding out for myself.
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  4. #4

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    I used an Agfa B2 to make a pinhole, and had the same set-up. I put the pinhole where the lens was and got a complete circular vignette. I haven't tried changing it to the front yet, but I think it's going to vignette in either spot. (How's that for an unhelpful answer?) I'd be very interested in how yours works out, just to satisfy my curiosity. I'm sure someone is going to come along and throw some serious math at this question and give you a real answer.

  5. #5
    SMBooth's Avatar
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    I think you need to mount it on the 5mm hole, otherwise it will interfere with light path.

  6. #6

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    a pinhole will vignette a bit because it doesn't spread light as well as a glass lens. I would think putting the pinhole where the lens is would give it the same angle of view as the lens, and then you can use the camera's viewfinder!

  7. #7

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    I don't mind some vignetting, but I want to avoid the "looking through a drinking straw" look.

    Mounting at the 5mm aperture might be better from a light transmission standpoint, but it is the least convenient option. Checking the current setup with a flashlight and ground glass suggests significant vignetting. I'm going to make up another plate to try in the forward mounting point and see what it looks like.
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  8. #8
    DWThomas's Avatar
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    In theory you could plot out a scale drawing using the film frame dimensions and distance from film to pinhole, aperture, etc. But in fact, it can be pretty challenging to get accurate measurements. The film/frame diagonal defines the minimum circle of coverage to avoid vignetting. Drawing a pair of lines from each end of the diagonal and crossing at the pinhole lays out the limits. Then the issue is plotting in any other "stuff" accurately to see if it encroaches on those lines. It's probably easier to load cut pieces of film and make test exposures.


    Click image for larger version. 

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    (Some day I may learn to use this CAD package ....)

    The numbers there are extremely loose guesses based on general 6x6 format and your comments.

  9. #9

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    That is an extremely helpful diagram - thanks. Since the camera is so easy to take apart, I'll take some measurements and see what I come up with. Stay tuned.
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  10. #10

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    Well, a few measurements and a quick sketch tells me that my plan isn't going to work unless I can get the pinhole closer to the aperture in the shutter plate. For anyone who might want to do such a conversion, the easiest way to this it is going to be to insert the pinhole plate from the front of the camera, into the very bottom of the conical well; short of mounting it directly to the shutter plate, which would require removal of the shutter mechanism, that's as close as you can get and it should prevent vignetting. For the moment I think I'm just going to reassemble the camera in its original form and use it that way. I'll come up with another pinhole project for the short term.

    Thanks for all the help.
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