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  1. #41
    ausphoto's Avatar
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    Well, having once been a German, it was/is my experience that Germans DO write their sevens with a horizontal bar mid-way down the stem, and most Germans would have a little ascender on their '1' and not just a straight stroke "|"...
    Certainly the '7' was the rule ten or so years ago (to distinguish it from the '1'...) and this thing is not a new lens...so, I'd take that as a reasonable assumption..

    But the clincher for me is that the measurements are Imperial and not Metric...

  2. #42

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    An assumption that may appear reasonable. Yes. But appearances can, and will, be deceptive.
    (Have a look at how sevens appear on Zeiss lenses, for instance.)



    Anyhow: the imperial measurements offer more 'solid' evidence.
    Could still be, of course, that a lens maker normally using metric units supplied optics to be mounted inside units made by someone using imperial units.

  3. #43
    ausphoto's Avatar
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    Managed to design a quick and dirty lens mount an stick the lens on a tripod. That allowed me to estimate the focal length a bit better. Looks like that the effective focal length of the lens is 24 inches. This means, given the diameter of the first element, it's more likely to be an f5.6. Doesn't look as powerful as the aerial lenses should be...but have put out various feelers beyond APUG

  4. #44
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    Doesn't an aerial lens need to be wide field?

    I don't really know much about aerial photography, but 24 inches onto a 10 piece of film doesn't seem very wide.

    What am I missing?
    Michael Batchelor
    Industrial Informatics, Inc.
    www.industrialinformatics.com

    The camera catches light. The photographer catches life.

  5. #45
    Marco B's Avatar
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    Quote Originally Posted by michaelbsc View Post
    Doesn't an aerial lens need to be wide field?

    I don't really know much about aerial photography, but 24 inches onto a 10 piece of film doesn't seem very wide.

    What am I missing?
    Entirely depends on the flying height. "Normal" aerial photography can be done at modest heights and may use smaller focal lengths, but I remember reading a recent article about US spy plains flying at heights up to above 10 km, and they used cameras with focal lengths inbetween 20-40 inches if I remember it well...
    Last edited by Marco B; 09-30-2010 at 07:33 AM. Click to view previous post history.
    My website

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  6. #46
    Marco B's Avatar
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    One thing that bugs me about the "aerial" camera lens identification, is that the "mount" in the middle of the lens just contains 3 fragile bolts. Just imagine these being subject to the vibrations of air turbulence... Unless this lens was somehow securely "clamped" down in a structure we don't see, I can not imagine how it would hold.

    And compare that with the many thread holes on this Fairchild aerial camera lens below (at least what they appear to be, I don't know much about these aerial cameras, maybe it is something different). I already see some 4 holes(?) for bolts this side of the lens, and I guess it is bolted down with 8 or 9?

    But maybe someone else knows better how these lenses were fitted in the aerial cameras...

    This is a lens made by Fairchild Space & Defense Systems:


    From this page:
    http://www.aerialphotolab.com/apl_museum.htm

    And here is an F56 aerial camera with 40 inch lens:



    From this page:
    http://mysite.verizon.net/yenrav/20cms/cameras.htm

    Quote Originally Posted by ausphoto View Post
    Managed to design a quick and dirty lens mount an stick the lens on a tripod. That allowed me to estimate the focal length a bit better. Looks like that the effective focal length of the lens is 24 inches. This means, given the diameter of the first element, it's more likely to be an f5.6. Doesn't look as powerful as the aerial lenses should be...but have put out various feelers beyond APUG
    Last, according to this Camerapedia page, the K-17, K-18 and K-22 came in versions with 24 inch / F6 lens option. So your values seem anything but strange...
    My website

    "The nineteenth century began by believing that what was reasonable was true, and it wound up by believing that what it saw a photograph of, was true." - William M. Ivins Jr.

    "I don't know, maybe we should disinvent color, and we could just shoot Black & White." - David Burnett in 1978

    "Analog is chemistry + physics, digital is physics + math, which ones did you like most?"

  7. #47
    ausphoto's Avatar
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    Thanks for the link to arialphotolab..!

    See here for lens mounted in makeshift bracket:
    http://www.flickr.com/photos/heritag...es/5038518501/

  8. #48
    Marco B's Avatar
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    Here is what is apparently one of the camera systems used on the U-2 spy plane, with a rotating lens unit. The U-2 had a serious payload limit (see this Google Books link), so they had to adjust existing K38 cameras. Maybe that explains the "holes" in the lens? Simply safe weight wherever possible?



    And three other images of a different camera system that was definitely on the U-2. Unfortunately, the pictures are not clear enough to fully understand the lens/shutter assembly and how it was fitted to the rest of the camera body:







    From this page: http://www.nationalmuseum.af.mil/fac...et.asp?id=9169
    My website

    "The nineteenth century began by believing that what was reasonable was true, and it wound up by believing that what it saw a photograph of, was true." - William M. Ivins Jr.

    "I don't know, maybe we should disinvent color, and we could just shoot Black & White." - David Burnett in 1978

    "Analog is chemistry + physics, digital is physics + math, which ones did you like most?"

  9. #49
    Marco B's Avatar
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    Quote Originally Posted by ausphoto View Post
    Thanks for the link to arialphotolab..!

    See here for lens mounted in makeshift bracket:
    http://www.flickr.com/photos/heritag...es/5038518501/
    Wow, that really makes you appreciate the size of the beast!
    My website

    "The nineteenth century began by believing that what was reasonable was true, and it wound up by believing that what it saw a photograph of, was true." - William M. Ivins Jr.

    "I don't know, maybe we should disinvent color, and we could just shoot Black & White." - David Burnett in 1978

    "Analog is chemistry + physics, digital is physics + math, which ones did you like most?"

  10. #50
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    An intriguing thread.

    One possibility that seems not to have been mentioned is that the holes were added for a special purpose, unrelated to the original application. In the 1950s there was a lot of military interest in rocketry and missilery, and not much on the market in the way of specialized tracking cameras. (There are historical pictures of tracking cameras built on antiaircraft gun mounts and the like.) The holes may have been put in simply to allow the lens to more rapidly equilibrate in temperature when exposed to cold (high altitude, perhaps, or actic conditions), or to prevent damage during rapid depressurization. And maybe it is one-of-a-kind because the idea turned out not to have been very good!

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