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Thread: TWO mysterious lenses

  1. #1
    renes
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    TWO mysterious lenses

    I bought these two lenses and have not found an information about them.

    First one is Dallmeyer Finder Anastigmat 4" lens. It's in barrel, very small, seems a Cine lens but never heard "Finder" name under Dallmeyer.

    Second one is marked only with A M letters with crown stamp in between - looks like englaring lens but nor for sure (see picture) and who is the maker.

    Hope someone knows anything.

    Attachment 117702

  2. #2
    dave_whatever's Avatar
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    Re: TWO mysterious lenses

    I think the AM means "Air Ministry" - i.e. a lens made for the British gov, probably for aerial recce work?

  3. #3

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    Re: TWO mysterious lenses

    More likely ordinance/bomb sights or training/hit recording camera. There are some who have good knowledge of the various cameras used by the RAF. Most gun camera optics have grub screws to keep the cells in place due to excessive vibration!

  4. #4

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    Re: TWO mysterious lenses

    That looks like an f4 in the picture. The only lens with that maximum aperture, that I know of, that was made for the military, was the Ross 5" F4. However they are usually in a very different mount.

  5. #5
    renes
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    Re: TWO mysterious lenses

    That's right, it's 5" with f4 to f11 with 16 aperture blades. Both glasses are convex outside, really strong. Is it anastigmat? I see - if corectly - 2x 4 reflections.

    Attachment 117706

  6. #6

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    Re: TWO mysterious lenses

    It is a plasmat. One of the first. It is a moderate wide angle. Covers about 70 degrees. Will cover 5x7 . Perhaps a bit more. It is actually an f3.1 lens. It has an extra large front element. I think the idea was to even up the illumination on the plate. Civilian versions of lens are engraved E.M.I. I think it stands for Extra Marginal Illumination or maybe it is Extreme. Not sure which. They used them on the torpedo cameras and for aerial survey work. Seen from that angle the mount is of the type usually seen. It maybe possible to stop the lens down more than f16. Some you can, some you cannot.

  7. #7
    renes
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    Re: TWO mysterious lenses

    Confirmed, front lens is larger, 41mm in diameter what gives f/3.1. And aperture goes beyond f11, a few mm further.

    Really fast WA vintage lens for 5x7! It's like 27mm on 35mm camera (lens equivalents for 5x7)?

  8. #8

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    Re: TWO mysterious lenses

    Quote Originally Posted by renes View Post
    That's right, it's 5" with f4 to f11 with 16 aperture blades. Both glasses are convex outside, really strong. Is it anastigmat? I see - if corectly - 2x 4 reflections.

    Attachment 117706
    It is a lens from a Torpedo camera. Google it to find all about it.

  9. #9

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    Re: TWO mysterious lenses

    Quote Originally Posted by renes View Post
    That's right, it's 5" with f4 to f11 with 16 aperture blades. Both glasses are convex outside, really strong. Is it anastigmat? I see - if corectly - 2x 4 reflections.

    Attachment 117706

    It is a Ross wide angle lens.
    http://www.ebay.com/itm/Ross-Wide-An...item3ce1c83623

  10. #10

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    Re: TWO mysterious lenses

    I agree with Jesse, it's a Ross 5 inch wide angle lens. I've got one just like it. Not all these lenses were marked by Ross to show that they manufactured them. The 14A shows that it is a lens made for a government contract and the AM indicates that it was for the Air Ministry.
    I've seen an image in a book by St Ansel taken with one of these lenses so they can't be too bad.
    Pete.

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