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Thread: on the verge camera build

  1. #31
    500+ Posts earlj's Avatar
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    Don - that is a masterpiece of DIY! I hope the images are as impressive as the instrument!
    because:
    "a squid eating dough in a polyethylene bag is fast and bulbous, got me?"
    -Don Van Vliet

  2. #32
    Thanks for the kind words Earl.As I was going to test it with some paper negs today a series of storms came through and kept on till I gave up,We've got out of town company coming tomorrow staying through the weekend,buuuuuut next week I'm hoping for a window to take 'er out! The part I'm most concerned about is the light tightness of the film holder(got my fingers crossed).I'll post pics as soon as possible.Am anxious as you might imagine...
    Don

  3. #33
    Finally got to try'er out! After several "Honey do"s and a week out of town(with a few days to recover),made a couple of exposures today. The camera and traveling support worked fine but seems I need to do a little more work on the film holder.I used 5X7 sized paper negatives for the tests and found both were fogged on the slide edge of the holder,"A" was exposed with the slide removed and"B" exposed with the slide pulled to the edge but left in the holder.It appears there's less fog on "B".Also I shortened the exposure on "B" slightly as I thought "A" was over exposed a little.Think attaching some felt to drag on the slides might fix this issue.
    Overall things went well(better than expected with a new piece of equipment).I'm really liking the look of in camera paper negatives so an 11X14 paper purchase is coming soon..
    Don

  4. #34
    Been thinking of an improvement/update for the rolling camera platform.The 10" wheels are great for moving around on concrete and mowed lawns but not so much over rough terrain so am trying to score a couple of 20" bicycle wheels to make this type moving easier. Also toying around with the idea of a pinhole to replace the lens for fooling around but not sure about hole diameter so any thoughts will be appreciated.
    Don

  5. #35
    500+ Posts Ned.Lewis's Avatar
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    I'd make the pinhole for the shortest "focal length", i.e. with the boxes collapsed all the way. Probably somewhere close to 0.5mm, but would need the length to do an optimized calculation.. Wow that's a great project!
    Some photos: Ipernity
    ( pinholes and solargraphs mixed in among the rest)

  6. #36
    It just seems the opportunities just keep coming.As I'm working on another project my mind keeps finding more fun things to do with the ones that are completed.
    This will allow trying pinhole pics( which I've not done for probably 50 years or more) and use my newly found affection for in camera paper negatives as well, should get the most use/fun out of the new camera as I can.
    Ned I'll measure the camera collapsed and post it soon,thanks for the suggested hole dia.
    Don
    Last edited by blindpig; 12-18-2014 at 04:29 PM.

  7. #37
    Ned, the extension collapsed is 21" (I new that DUH! )don't know why I didn't remember. Couldn't be age related,must be because the files are too big to recover stuff quickly....

  8. #38
    500+ Posts Ned.Lewis's Avatar
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    I'm sure that's it. My files are way too big!
    Off to see my daughter play in a school concert right now, but I'll calculate it this evening! Bigger than 0.5mm, I was imagining a shorter FL.
    Some photos: Ipernity
    ( pinholes and solargraphs mixed in among the rest)

  9. #39
    500+ Posts Ned.Lewis's Avatar
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    Different people use slightly different formulae, but for shooting outdoors on paper here's what I'd try:

    21 inches * 25.4 mm/in = 533.4mm "focal length".

    "optimum" diameter = 1.65 * sqrt( 450*10^-6 * 533.4 ) = 0.81mm

    450nm is roughly the wavelength of blue light, but I'm seriously starting to think that a smaller value to account for UV is more appropriate for most of my paper negatives. Whenever I err on the side of a slightly smaller hole, it seems like the results improve more than the math says it should. So I'd probably aim for about 0.7 even after this calculation, or use 0.8 if you think you'll use it more indoors with artificial light.

    Have fun!

    my 2 cents!
    Some photos: Ipernity
    ( pinholes and solargraphs mixed in among the rest)

  10. #40
    Thanks Ned,
    I'm going to search my stash for shim stock I recall having and mic some drill bits for the proper size.Now is a good time for this type of thing as the weather is treating us poorly(only a few minutes of sunshine this last week and being solar powered it's not helping my progress on the paper negative to carbon print enlarging /copy project).The temperature in the shop/garage has been in the 30's as well adding to the slow down.
    Guess I can't blame the large files on this one,must be age related LOL!
    Thanks again Don

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