Good Primer

Discussion in 'Pinhole Photography' started by picturetaker, Jul 1, 2006.

  1. picturetaker

    picturetaker Member

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    Having looked at the Eightbanner photos, I have a severe GAS attack. But before I get carried away, where can I find a 'good' primer on pinhole cameras, their use, their value etc. I am mostly into rangefinders with some SLR and a bit of digital. Now I find out about pinhole cameras - will GAS never end :-]
     
  2. ann

    ann Subscriber

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  3. picturetaker

    picturetaker Member

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    Thanks for the link. Lots there to sink my teeth into .... now where did I put that coffee can?
     
  4. Jim Jones

    Jim Jones Subscriber

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    For calculating pinhole diameters and focal lengths try Pinhole Designer For optimum on-axis sharpness with this program I recommend a user constant of 1.5. Contrary to popular opinion an accurately calculated and fabricated pinhole is important for optimum performance. Another site with much good information is http://home.online.no/~gjon/pinhole.htm A paper by Matt Young has reliable technical information. Eric Renner at www.pinholeresource.com may well be the world's foremost authority on pinhole photography. His book, Pinhole Photography, is a fine source of historical, technical, and esthetic information on the subject.
     
  5. Greg_E

    Greg_E Member

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    Thanks for the tip, I've been wondering about the different constants. I simply planned on trying the 3 sizes I have coming on my 140mm FL project (17 degrees angle of view, 35mm film size) to see what I liked best. I'll probably set up a "studio" shoot with a hot light or two so that motion won't be an issue. That will also give me the ability to stay far away from reciprocity.

    http://www.f295.org has pinhole specific forums! Sometime things spill over into the alternate forum (which is where the "designs" for my 35mm project currently reside).

    Also, you can use some of your existing cameras to try out pinhole photography. Get a spare body cap for your SLR, and cut a hole in it. Affix an aperture to that hole. Take pictures. Tripods are recommended!
     
  6. Jim Jones

    Jim Jones Subscriber

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    I recommend the constant of 1.5 based on calculations and testing. There is a peak in resolution at the optimum pinhole diameter. A pinhole can resolve line pairs with a spacing less than the pinhole diameter, contrary to what a few authorities seem to believe. However, the off-axis sharpness suffers. Interestingly, a pinhole about twice the optimum on-axis diameter covers 90 degrees with fairly even resolution, although this resolution is conspicuously less than from an optimum diameter. Also, corner illumination falls off by two stops at 90 degrees coverage. This is unavoidable in pinholes and older wide angle lenses. The design of some newer lenses reduces this falloff somewhat.

    Thanks for reminding us of F/295. There are some very imaginative camera designs and photos on the site.
     
  7. Greg_E

    Greg_E Member

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    Well that constant lines up more with the pinholes I have coming. I have a .4, .3, and .2mm pinhole in the mail. Popping the 1.5 constant into Pinhole Designer with my 140mm FL I get a diameter of .416 which seems even more favorable with the choice of pinholes I already made. Since the image circle at that FL is so large, I shouldn't have any problem with the corners. I'm still wondering if a smaller pinhole will give me any greater resolution, but I guess testing will tell soon enough. The project I'm working on is here:
    http://www.f295.org/DIYforum/cgi-bin/forum/Blah.pl/Blah.pl?b-misEquip/m-1150231036/
    May not be as elegant as a wooden camera, and it should have been simple, but is turning out to be anything but simple. I need to get working on the timer kits to get this thing going.