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  1. #11
    ambaker's Avatar
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    Have you tried shooting with the lens?

    This page has some, to me anyway, fascinating info on lens damage.

    http://www.lensrentals.com/blog/2008...ment-scratches


    Sent from my iPad using Tapatalk HD

  2. #12

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    Quote Originally Posted by himself View Post
    how would I determine the curvature?
    Opticians have a machine that can do this. It is used to determine the prescription for glasses when the original paper prescription has been lost.
    A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.

    ~Antoine de Saint-Exupery

  3. #13
    ic-racer's Avatar
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    Just glue it back together. What is the concern, are you afraid the crack might improve the optical performance?

  4. #14

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    If you can find a histology/microscopy lab, scrounge some DPX slide mountant. It's a thin, clear resin, dries quickly. I believe auto windscreen repairers use something similar. My bet is that if you glue the two parts neatly without too much resin, and carefully cut away any surplus with a sharp knife (glass is harder than steel), you won't be able to see any difference in performance.

  5. #15

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    Ian,

    That would be very kind of you, the element has a 50mm diameter and is 5mm thick. I'd owe you a favour then.

    Ambaker,

    Some good news on there and considering the fact that I have to make a ground glass anyway, this now gives me reason to do it sooner rather than later.

    Thanks Jonathan and Gerald, I'll be trying that too.
    And to you ic-racer, how very dare you, you sir are outrageous

  6. #16

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    What's the construction? Is it a petzval? If the front is a cemented pair, it'll make a nice meniscus lens with FL about twice the lens, and lots of coverage (and funky effects). I have a set of photos on flickr from a lantern lens minus the rear elements. Before you do anything else, try reassembling the two halves into the frame and shooting through it. You can also paint the broken edges with a sharpie (which is easily removed). And, the attached photos were taken using the shown Goerz Syntor ( a 4 element dialyt type - I dropped the front while cleaning it). There's some ghosting and loss of sharpness but I didnt blacken the edges.

    DanClick image for larger version. 

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    Last edited by Fotoguy20d; 05-13-2013 at 09:37 AM. Click to view previous post history.

  7. #17

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    Quote Originally Posted by Fotoguy20d View Post
    What's the construction? Is it a petzval? If the front is a cemented pair, it'll make a nice meniscus lens with FL about twice the lens, and lots of coverage (and funky effects). I have a set of photos on flickr from a lantern lens minus the rear elements. Before you do anything else, try reassembling the two halves into the frame and shooting through it. You can also paint the broken edges with a sharpie (which is easily removed)./ATTACH]
    It's probably a petzval (cemented pair at the front, then one larger element, a small spacing and a third thin element at the rear. It looks similar to the Dallmeyer design - but is unnamed)
    Using it as a meniscus would be a bit problematic, the focal length would be close to 30", which is way too long for anything I have planned.

  8. #18
    TheFlyingCamera's Avatar
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    Ok- Fotoguy's broken lens example is more extreme even than I was thinking - Jim Galli once had a rare Cooke (or Pinkham & Smith, or some such portrait lens) that the front element looked like someone hit it with a hammer, but it still made excellent images so long as you zealously shaded the front to avoid flare. I think he had it in the classifieds here, or maybe it was a thread - search the forums for it.

  9. #19

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    I just finished grinding my view screen (without breaking it), so after a bit of lunch I'll check out just how bad it is...
    problem is, I don't have a before-the-brake to go off, so as long as there are no obvious problems I'll count myself lucky

  10. #20

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    I just made a very quick and ugly box camera and it doesn't seem to effect it to a noticable degree...

    lucky me then.

    now, to glue or not...

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