Does anyone know of a table with cross-references (to modern filter designations, maybe Kodak Wratten) and filter factors for Zeiss filters? I am thinking specifically about filters for the Contax rangefinders (40.5mm or 42mm push-on), but a generic reference including these is fine (and quite helpful). Some examples are R10 (light red), GR3, G2,3,4 (yellows: light through orange), as well as the Zeiss Jena designations such as gelbglass L42 (light yellow). This could also include the Zeiss Ikon filters (such as the B50 bayonet mount filters). I am thinking more about B&W filters, but open to more. I know I am asking a lot, but I am struggling to find this information on the web. For instance here is some useful information (i.e., some good cross-reference, but no filter factors):
Some of my Contax ones are, and my Zeiss Ikon B50 one are also. Most of the Contax ones do not. Maybe the designations G2, G3, G4 mean gelb (yellow), filter factor 2,3,4? R10 (light red) would be filter factor 10 (I would think 8, but could be different for Zeiss)? GR5 (green, filter factor 5)?
I have one chrome rim filter marked "Zeiss Ikon Stuttgart Green 2x", GR2?
Yes that makes sense. "G" (gelbe, yellow), "GR" (grün, green), "R" (rot, red). Not sure that the numbers correspond to filter factors unless marked as 2x, 3x etc.
Yes that makes sense. "G" (gelbe, yellow), "GR" (grün, green), "R" (rot, red). Not sure that the numbers correspond to filter factors unless marked as 2x, 3x etc.
I suspect they are not. The one (GR 2x) is, the rest I think are just designations. I have an idea what the filter factors are, and I have a light meter, but would be interested in seeing what Zeiss claimed.
According to my opening link ( http://www.earlyphotography.co.uk/site/entry_M17-1.html ), R10 = A, 25 Wratten which sounds like the typical 25A (filter factor = 8). I think G2 is a medium yellow (2x) or K2,8 Wratten; and GR3 maybe light green (not sure what filter factor is, don't use green much). GR3 is not in the linked table. I have Zeiss GR5, and by the light meter test it is 2x, so sounds like medium yellow-green (table says GR5 is yellow/green). I do not have a GR3.
I would follow another approach:
To my understanding all german made all-glas filters are made wth glass from only two sources, Schott glassworks in Jena and in Mainz. Thus the number of raw-glass varieties is limited.
I would follow another approach:
To my understanding all german made all-glas filters are made wth glass from only two sources, Schott glassworks in Jena and in Mainz. Thus the number of raw-glass varieties is limited.
Heliopan appears to be the current purveyor of Schott glass filters. The key to the mystery of Zeiss filters may lay hidden in plain sight in the cryptic Latin at the end of their History web page,
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The last cryptic line Google translates to "However, the jaws do not need any members". A clue?
-) my idea was, if two german all-glass filters look alike by sight, they are likely identical
-) that cryptic text is a placeholder text used in websites templates. Someone forgot to take it off.
So much about webpage designers and people reading their own sites...
-) that cryptic text is a placeholder text used in websites templates. Someone forgot to take it off.
So much about webpage designers and people reading their own sites...