Goerz Dagor speed mismatch - fake or rare?

[Moogie]

Hi forum friends,

I recently purchased a Goerz Dagor 270mm in the bay.

Now after arrival I am bit confused about 1 issue.
On the aperture ring it says f4.6 but on the inner ring showing the name, details and so on about the lens it shows f6.8.
So now I am confused if this might be a fake and just somebody added the inner ring to make it more valuable?
Nowhere on the lens, except this ring is any indication about the manufacturer.
On the other hand the lens seems to be of very high quality and the seller explained that this just might be a mistake of the production but that he is 100% sure this is an original.

What do you think?

[Tracy Storer]

It's very possible the barrel is marked in some other system of aperture measurement. I had a 10.75" Dagor that was marked in US (universal System) stops. The barrel looks like a Goerz barrel. If you lis the stops as marked, we can tell you what system the markings are and what the related "f stops" are.

[mdarnton]

First guess would be that someone took the cells and put them in a new mount from another lens to replace one that was damaged. One sees this quite a bit on Ebay with shutters that obviously are replacements, with the wrong f-scale.

edit: OK, magnifying one of the photos, I think I agree with Tracy. It looks like the numbers double, which would be some other system.

There's a table here, and a discussion:
http://throughavintagelens.com/2010/...f-stop-system/

[Dan Fromm]

Look up Stölze scale.

[mdarnton]

I'm not bad at google, but I find nothing. How about some real help?

[Louis Pacilla]

I'm not bad at google, but I find nothing. How about some real help?

I just Googled F stops & got this table which I already had a screen shot of. https://en.wikipedia.org/wiki/F-number If you scroll down half way on this page you will find the Comparative Table Of Diaphragm Numbers

I believe this is the Goerz iris stop #'s as it matches up well w/ f stop readings as f 6.8 is just about right on the Goerz stops. Goerz # 4.5-6 = f stop 6.8

[William Whitaker]

Looks like an early Dagor. I had a 12-inch that looked exactly like that. Was marked "Doppel-Anastigmat" or "Dopp-Anastigmat" as I believe yours is. (But it's difficult to tell from the photo.

[Dan Fromm]

I'm not bad at google, but I find nothing. How about some real help?

<obscenities deleted>

I've just added a spreadsheet with the scales and formulas behind them to the list. If you need help finding the list, try the stickies in the lens section.

[Louis Pacilla]

<obscenities deleted>

I've just added a spreadsheet with the scales and formulas behind them to the list. If you need help finding the list, try the stickies in the lens section.

Brother Dan do you mean you put together a spreadsheet w/ explanations for the Comparative Table Of Diaphragm Numbers I posted in post #6

[Steven Tribe]

This is quite a common alternative F scale around 1900. The selection of the scale used was based on the market to which it was being exported to.

Suter followed Goerz as shown below in a 400mm Anastigmatic from the same period - this is a F6.8 lens too.