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  1. #11
    X. Phot.
    Just curious. I've experimented with .5mm pinholes on 4x5 and 8x10 cameras (FL=170mm ~ 300mm), but never achieved what appears as barrel distortion in your last image. It must be the short FL.

  2. #12
    ced
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    X. Phot. No it is the outer lens housing of the lens that was removed and I have since removed the rim to clear the way to the pinhole.
    If you are familiar with the Agfa Clack see my sketch:http://www.flickr.com/photos/6720285...n/photostream/
    This link one of many:http://sv.wikipedia.org/wiki/Fil:Agfa_clack_sst.jpg

  3. #13
    keithwms's Avatar
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    Quote Originally Posted by ced View Post
    Just wondering if anyone at this forum has any experience with measuring resolution on film/paper with a pinhole system?
    What is the highest attainable resolution with medium iso film for example?
    What about DOF any interesting observations?
    My apologies if this has previously been covered here.
    If you look around, I think you will find a thread in which Ralph Lambrecht gave some very helpful comments. Basically, there is more than one way to define resolution.

    Ah yes, here it is:

    http://www.apug.org/forums/forum62/6...hole-size.html
    "Only dead fish follow the stream"

    [APUG Portfolio] [APUG Blog] [Website]

  4. #14
    ced
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    keithwms Thanks for pointing this out to me and very informative it is too.

  5. #15
    ced
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    Three of the latest tests I made at the link below, in the comments below the images there is more info, any comments are welcome.
    http://www.flickr.com/photos/67202854@N05/

  6. #16
    RalphLambrecht's Avatar
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    Quote Originally Posted by Jim Noel View Post
    Resolution is dependent on the crispness of the edge of the pinhole and the size relationship between the pinhole and the distance to the film.
    DOF is essentially from a few inches in front of the camera to infinity.
    I am quite sure this has been covered in far more detail elsewhere on this and other forums.
    hreis my take on this:
    Regards

    Ralph W. Lambrecht
    www.darkroomagic.comrorrlambrec@ymail.com[/URL]
    www.waybeyondmonochrome.com

  7. #17
    RalphLambrecht's Avatar
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    Quote Originally Posted by ced View Post
    Just wondering if anyone at this forum has any experience with measuring resolution on film/paper with a pinhole system?
    What is the highest attainable resolution with medium iso film for example?
    What about DOF any interesting observations?
    My apologies if this has previously been covered here.
    a pinhole is an ideal only(diffraction-limited) lenscalculate the diffraction limit to get the pinhole resolution
    Attached Files
    Regards

    Ralph W. Lambrecht
    www.darkroomagic.comrorrlambrec@ymail.com[/URL]
    www.waybeyondmonochrome.com

  8. #18
    Jim Jones's Avatar
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    I googled for a quality download of the USAF 1951 reslution test chart, but only found small or jpg files. This gif chart, small enough to post here, can be replicated to assemble a large chart for comparative testing of pinhole images. Print it without resizing to prevent introducing artifacts. The finest bars will not print perfectly due to dot spread. Actual line pairs per mm can be calculated. This was not included, as it would restrict the versatility of the chart. Feel free to post or publish it elsewhere. This is the information age, and knowledge should be as free as practical.
    Attached Thumbnails Attached Thumbnails FlmRes64b.gif  

  9. #19
    ced
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    Here again as posted earlier a link to some charts I made for you to use if you wish.
    I will welcome any critic for improvement or inaccuracy found.
    https://picasaweb.google.com/1108229...t5IlGtmohk4WJw

  10. #20
    RalphLambrecht's Avatar
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    Quote Originally Posted by Jim Jones View Post
    I googled for a quality download of the USAF 1951 reslution test chart, but only found small or jpg files. This gif chart, small enough to post here, can be replicated to assemble a large chart for comparative testing of pinhole images. Print it without resizing to prevent introducing artifacts. The finest bars will not print perfectly due to dot spread. Actual line pairs per mm can be calculated. This was not included, as it would restrict the versatility of the chart. Feel free to post or publish it elsewhere. This is the information age, and knowledge should be as free as practical.
    feel free:http://www.darkroomagic.com/Darkroom...estPattern.pdf
    Regards

    Ralph W. Lambrecht
    www.darkroomagic.comrorrlambrec@ymail.com[/URL]
    www.waybeyondmonochrome.com

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