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Thread: Searching for info on BL 4.5 lens with minimal markings...

  1. #1
    Embdude's Avatar
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    Searching for info on BL 4.5 lens with minimal markings...

    The lens is marked BL and has no shutter and aperture is marked 4.5-16. It is a very dark olive drab color.
    It has a date painted near the mount- Nov 28 1966 and a -8 is painted on the side as well as written in pen on an inspection sticker.

    From what little I have found online it likely came from a Xerox machine.

    I held it up to a piece of printer paper and to my surprise it covered it with no problem. I had assumed being a 4.5 it was likely a Tessar design but it is about a third smaller than my other Tessars with similar coverage.

    If anyone knows about this lens I would really like to know-

    Focal Length
    Lens Design
    Best way to open it for cleaning
    impressions of it as a camera lens
    what the -8 is indicating

    Click image for larger version. 

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  2. #2

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    Re: Searching for info on BL 4.5 lens with minimal markings...

    I assume it's close to later Fujinon-Xerox lenses, 240mm f4.5 to f16, or 260mm?

    Meant for high contrast, low resolution use in a Xerox machine.

    https://www.photo.net/discuss/thread...-board.256822/



    Sent fra min SM-G975F via Tapatalk

  3. #3
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    Re: Searching for info on BL 4.5 lens with minimal markings...

    Thanks!
    Quote Originally Posted by Oslolens View Post
    I assume it's close to later Fujinon-Xerox lenses, 240mm f4.5 to f16, or 260mm?

    Meant for high contrast, low resolution use in a Xerox machine.

    https://www.photo.net/discuss/thread...-board.256822/



    Sent fra min SM-G975F via Tapatalk

  4. #4
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    Re: Searching for info on BL 4.5 lens with minimal markings...

    Ok so I took the lens apart for cleaning, it is not a Tessar as I had thought. I don't recognize the layout... kinda of a symmetrical Tessar... Anyone know this design?
    Click image for larger version. 

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  5. #5
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    Re: Searching for info on BL 4.5 lens with minimal markings...

    Click image for larger version. 

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    The one on the end on the right is just the retaining ring not a lens. There are spacers on either side of the concave element...

  6. #6

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    Re: Searching for info on BL 4.5 lens with minimal markings...

    Reminds me of most modern plasmat and macro lenses. Take a look for your self http://www.prograf.ru/rodenstock/largeformat_en.html

    Sent fra min SM-G975F via Tapatalk

  7. #7
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    Re: Searching for info on BL 4.5 lens with minimal markings...

    Thanks, yes it looks very much like the first one - Apo-Sironar-N

    Looking over the diagram I drew in comparison to the Sironar I have tried to redraw it a little...

    Click image for larger version. 

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    Also some searching on the web shows similar but likely later model BL lenses in the focal length of 209mm... I will need to test out the FL of mine to see if it is the same..

  8. #8

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    Re: Searching for info on BL 4.5 lens with minimal markings...

    This is very interesting. By coincidence I was bored today and pulled out some old lenses I squirreled away and just rediscovered this lens. Click image for larger version. 

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  9. #9
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    Re: Searching for info on BL 4.5 lens with minimal markings...

    Quote Originally Posted by profvandegraf View Post
    This is very interesting. By coincidence I was bored today and pulled out some old lenses I squirreled away and just rediscovered this lens. Click image for larger version. 

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    Yes that is the same lens as mine except yours is a +2 and mine is a -8... I wish someone could explain the significance of the number...

    There is an auction on ebay with a similar but not quite identical lens set...

    "5 Bausch & Lomb (B&L) copy lens set with mount. They are all the same lens: 209mm F4.5 BUT they have different visual corrections. Corrections on the lens: -3 ,-8 ,+4, +4, +12"
    https://www.ebay.com/itm/26500101100...rEeqDADhx1iSqY

  10. #10

    Re: Searching for info on BL 4.5 lens with minimal markings...

    Corrections on the lens: -3 ,-8 ,+4, +4, +12" did you find an explanation? whats the IQ like.

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