35mm pinhole camera

Discussion in 'Beyond the Basics' started by benjyman345, Feb 4, 2007.

  1. benjyman345

    benjyman345 TPF Noob!

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    hello,

    I was thinking of making a pinhole camera using my film SLR and an old lens cap with a hole drilled through, then black foil placed over the hole with another tiny hole made using a pin in the foil.

    Some articles on this suggest that you can still use the light metre but I don't think my camera has a light metre which works for more than 30 seconds... although i cold be wrong. (Pentax MZ50) If not how do i decide on exposure times?

    This is an example of a photo from a website, taken with a 35mm pinhole camera made using the method above and the photo is all blurry and out of focus.
    http://www.debevec.org/Pinhole/pinhole-debevec.jpg
    Surely it shouldn't turn out all blurry and out of focus like that???

    Also would you suggest using B&W or colour film for my first pinhole camera?

    thanks
     
  2. Steph

    Steph No longer a newbie, moving up!

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    I don't think your camera meter would be able to measure light passing through a pinhole as it is far too small. You would have to measure the light with a lens fitted to your camera (or use a handeld meter) and compoensate for the size of the pinhole (see link below to calculate exposure times).

    The sharpness of the picture will depend on the size and shape of the hole. There are ways of calculating the optimal hole size (see links). If you make the holes yourself, just experiment to se which one gives the best results.

    As for colour or B&W both will work. Just keep in mind reciprocity failure as the exposure are going to be quite long. That might a problem with colour film as you can see a significant colour shift.

    To summarise, try to experiment even if you have to 'waste' a few films. It is really satisfaying to get a proper pinhole image.

    http://www.mrpinhole.com/calcpinh.php
    http://www.pinhole.cz/en/pinholedesigner/
    http://pinholeresource.com/
     
  3. benjyman345

    benjyman345 TPF Noob!

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    so how do I work out the "Focal Length" (from film to pinhole) on my SLR so that I can work out the optimal pinhole diametre using the "pinhole camera design calculator."

    thanks
     
  4. hazzayoungn

    hazzayoungn TPF Noob!

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    the focal length in this case is the distance from the pinhole to the film. an option to try and do this is to tak ethe lens off your cam and put it on bulb for long enough to stick a ruler in there...being careful of course. if youre scared of it though, you can estimate by measuring the outer frame of your camera.

    as for exposure, neg film is super forgiving, so measure your pinhole in fractions of mm and use the sunny 16 rule on mrpinhole. all my pictures looked about the same, though they were +-4 stops

    BSP: a bit more inspiring...theres quite a few groups on flickr with great results.
    http://www.flickr.com/search/groups/?q=pinhole
    these are from my encounter with the matchbox monster
    http://www.flickr.com/photos/89503142@N00/

    good luck, and dont forget to have fun
     
  5. hazzayoungn

    hazzayoungn TPF Noob!

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  6. Mike_E

    Mike_E No longer a newbie, moving up!

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    Question, If you were to put the pin hole adapted cap on an extension tube to get rid of the vignetting, how would that effect the photo as far as focus or would it at all?

    mike
     
  7. hazzayoungn

    hazzayoungn TPF Noob!

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    according to mrpinholes calculator, any focal length over 20mm will produce no vignetting on 35mm film

    20mm < 1 inch

    in other words...unless youve already tried and seen otherwise, vignetting shouldnt be a problem.

    i dont think focus would be too much of a problem, but someone can step in here and correct me

    i say this because chances are the pinhole will be a little dirty, grain may be obtrusive, diffraction will occur, f stop is usu btwn 50-200, and focal length is usu <50...meaning that might end up with a bunch of wide angle fuzzy pictures like i did. details at infinity for my pictures were still viewable, but fuzzy

    however (deviating from main topic...kinda) if you make a telephoto pinhole camera, the detail from far away objects will be much more crisp since they fill up more of the frame, but youll have to make the hole much larger to get crisp details to bump up the f stop, but as a result of a larger hole, the thing might come out much blurrier than initially expected, and exposure times shoot through the roof...

    hmm...i got a bit off topic there :confused:


    so to recap, focus shouldnt be affected, but it never hurts to experiment :wink:
     

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