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Thread: F-stop scale

  1. #11
    Klainmeister's Avatar
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    My scanner was able to resolve quite a lot of edge for me, so I smoothed it out, and got rid of any burrs with sandpaper, and double checked. Worked fine.
    K.S. Klain

  2. #12
    NedL's Avatar
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    You can use your enlarger, if you have one, to measure the diameter too. Put a clear plastic ruler in the carrier, measure ( for example ) how many mm a projected 2cm is, and then a little math to figure the diameter of the pinhole. I've only gone to this trouble twice. Usually I just put the pinhole next to a ruler with mm markings and look through a magnifying glass. You can measure to within a few tenths of a mm that way. My favorite pinhole camera was made like this.. it's something between .25 and .3mm and it doesn't matter a bit what it actually is because it makes great pictures.

    Another trick is to hold the pinhole up very close to your eye and look at something bright. You will easily be able to tell if the pinhole is round and if there are any substantial burrs.

  3. #13
    TheToadMen's Avatar
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    I use a simple microscope to view the pinhole. You can get one cheap secondhand.
    "Have fun and catch that light beam!"
    Bert from Holland
    my blog: http://thetoadmen.blogspot.nl
    my Linkedin pinhole group: http://tinyurl.com/pinholegroup


    * I'm an analogue enthusiast, trying not to fall into the digital abyss.
    * My favorite cameras: Hasselblad SWC, Leica SL, Leica M7, Russian FKD 18x24, Bronica SQ-B and RF645, Rolleiflex T2, Nikon F4s, Agfa Clack and my pinhole cameras

  4. #14
    marciofs's Avatar
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    The scan worked very well.

    I just bought some tools to make it proporcional, precise and sharp. Maybe I will be able to make a test today with a print paper.
    I cant wait to shoot with it.

  5. #15
    marciofs's Avatar
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    I made the first test today. 1 min exposute:

    Click image for larger version. 

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    But it is not in focus at all. Now I don't know if the hole is too big or too small. Or if the problem is something else. Maybe the problem is the paper going forwards?

  6. #16
    NedL's Avatar
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    If that is full bright sunshine in a white bathroom then 1 minute might be about right. Otherwise it seems like too short an exposure for a camera that is more than f/300 and a paper negative indoors. I'm guessing the pinhole might be too big. But it seems to be too much... I think it would have to be too big by a lot to produce this level of blur. Maybe the camera moved? I advise to try again, careful not to move the camera before spending time on another pinhole.

  7. #17
    marciofs's Avatar
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    Here an other testClick image for larger version. 

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    The problem is not the paper going forwards because I fixed it. I hope the hole is too small so I can correct it just by enlarging it.

  8. #18
    marciofs's Avatar
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    Quote Originally Posted by NedL View Post
    If that is full bright sunshine in a white bathroom then 1 minute might be about right. Otherwise it seems like too short an exposure for a camera that is more than f/300 and a paper negative indoors. I'm guessing the pinhole might be too big. But it seems to be too much... I think it would have to be too big by a lot to produce this level of blur. Maybe the camera moved? I advise to try again, careful not to move the camera before spending time on another pinhole.
    I actually calculated it again and now it seems to be f/36.

    This seccond shot was 2 sec about. Bright day but clouds hiding the sun.

    I am sure the camera didn't move at all. I will try make a hole smaller on a black hard paper to cover the original hole.

  9. #19
    marciofs's Avatar
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    I made a smaller hole and it is much better now...

    Attachment 68400

    But I don't know how to make a even smaller hole to improve it. It is too small..

  10. #20
    Klainmeister's Avatar
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    I'd use the pinhole calculator others have posted and find the 'optimum' pinhole size and go for that. Remember, they won't be terribly sharp no matter. I thought the first one was interesting the way it was.
    K.S. Klain

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