View Full Version : About Bausch & Lomb - Zeiss Unar series Ib 6.5x8.5

12-Apr-2011, 04:29
Hello. I've just purchased a Bausch & Lomb - Zeiss Unar series Ib 6.5x8.5, SN 772151 Pat 1900 (just Unar, not Portrait Unar). The aperture scale is strange. It marks 1.9 2 4 8 16 32 64. I go to google but there is less information. Just a few from wiki:

Probably inspired by the Stigmatic lenses designed by Hugh Aldis for Dallmeyer of London, Rudolph designed a new asymmetrical lens with four thin elements, the Unar Series Ib, with apertures up to f/4.5. Due to its high speed it was used extensively on hand cameras.
Anyone please let me know more about this lens. Thanks for reading.

Chauncey Walden
12-Apr-2011, 08:48
The aperture scale appears to be in US (Uniform Standard) stops which equates to f stops at 16 (US 8 = f/11, US 16 = f/16, US 32 = f/22, and so on) so what you read in Wiki appears to accurately describe it. Also see: http://www.cameraeccentric.com/html/info/bauschlomb_4.html

12-Apr-2011, 09:32
The first attachment is a general statement from the Kingslake book.... and the middle 2 pages are frrm a 1901 Zeiss Catalogue - all you ever wanted to know about the Ib Unar. The last page is also from the catalogue and explains B&L's (and othes) involvement.


12-Apr-2011, 22:02
Thank you Chauncey and Dan. That's enough.
I'll post some pics take with it next time. If they aren't special, maybe i'll let it go to the bay.