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

Attachment 224544 Attachment 224545 Attachment 224546

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/



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Thanks!

Quote:

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Originally Posted by Oslolens

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

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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?
Attachment 224578

Attachment 224579Attachment 224580Attachment 224581Attachment 224582
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...

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

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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...

Attachment 224645

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..

This is very interesting. By coincidence I was bored today and pulled out some old lenses I squirreled away and just rediscovered this lens. Attachment 224646

Quote:

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Originally Posted by profvandegraf

This is very interesting. By coincidence I was bored today and pulled out some old lenses I squirreled away and just rediscovered this lens. Attachment 224646

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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

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