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alexvaras
20-Nov-2018, 09:54
Hi all,

Finally I got this lens, I already dated it, it's from 1909-1911.
But being a f7,2 is the most intriguing fact.
I read a lost of old documents, english and french mainly but all the references for Tessar are f6,3, f4,5, etc.

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Anyone can add info about it? Is it like a transition lens from Zeiss double-anastigmat?
Confirmed the presence of two lenses at the front and a double-cemented at the back.

Thank you,
Alex

Dan Fromm
20-Nov-2018, 12:57
Alex, the Tessar is an asymmetrical anastigmat. It was CZJ's primary general purpose lens until after WW II. Not transitional.

CZJ's Ser. III Anastigmat was an f/7.2 four elements in two cemented groups lens, but it was discontinued before 1900.

Y'r lens may be in a small shutter that limits the maximum aperture.

alexvaras
20-Nov-2018, 13:21
The aperture at the Koilos shutter is 7,2 as well. It could fit another lens before this.
Until when Koilos did shutters? I will try to read about Koilos.

Dan Fromm
20-Nov-2018, 14:04
You could unscrew one of the cells and measure the shutter's aperture's maximum diameter ...

Steven Tribe
20-Nov-2018, 14:54
This air brake model of the Koilos was introduced in 1907 and it looks like it disappeared in 1910, leaving the Compound alone as an air brake shutter.

lucaas
20-Nov-2018, 15:59
As Dan said, the lens aperture is limited by the max opening of the Koilos shutter. Your shutter should be no.2 with 25mm opening.

alexvaras
21-Nov-2018, 05:00
At home I will measure the shutter max opening later, lens is from 1909 as I read in Zeiss Historica - Spring 1999 - page 15.
If Koilos was still on business (as Steven says) then it fits, it could be from another shutter yes but the lettering says 1:7,2 pretty clear but no catalog I read so far mention any lens like this.

Dan Fromm
21-Nov-2018, 07:26
Even in those days CZJ was a merchant lens maker, sold lenses to camera manufacturers. Special versions like the OP's f/7.2 Tessar weren't always cataloged for sale to the, um, general public.

OP, look for the lens in camera catalogs, not in CZJ lens catalogs.

alexvaras
21-Nov-2018, 11:14
The narrowest diameter is 24,21mm where the shutter blades come and go, the thread lens diameter is 30mm.
Dan, what does OP mean? I only know OverPowered acronym from online games and I don't think this is the case.

Dan Fromm
21-Nov-2018, 11:40
The narrowest diameter is 24,21mm where the shutter blades come and go, the thread lens diameter is 30mm.
Dan, what does OP mean? I only know OverPowered acronym from online games and I don't think this is the case.

Original Poster. That's you.

alexvaras
22-Nov-2018, 01:15
Thank you Dan, I will search on camera catalogs, it is going to be a long search :)