European f markings.

[Dean Lastoria]

I just got a brand spanking new old lens. It is German with European markings. I checked the back files here because this is probably a simple question, but I c ouldn't see it. The dial representation is arithmetic even though the stops are logarithmic, so does that mean that I just mark of where the modern #'s are and it will work? Simpler, it goes 4.5,6.3,9,12.5,18,25,36, so if I just make a strip of paper the same length as the bezel will it be accurate? Simpler-- how do I convert old f-stops to new f-stops? (My meter don't speak the old dialect). Dean

[M.]

These numbers are just exactly half stops between our current system. Thus f:4.5 is a half stop slower than f:4.0 and a half stop faster than f:5.6. You don't have to make any corrections, just read your meter halfway between the ISO apertures. The sequence is 1.0,1.1,1.4,1.7,2.0,2.2,4.0,4.5,5.6,6.3,8.0,9.0,11.0,12.5,16,18,22,25, 36,44,etc.

[M.]

Sorry, I left out 2.8,3.5

[Dean Lastoria]

Well, that makes sense - simple, logical -- you can see that math intimidates me. Thanks a lot.

Dean