Question on leica filter.

[Fabian]

Hello there.

I bought myself a Nr. 1 yellow filter for my summitar.

My first question is how many stops do I have to open up, one or two?

It has some cleaning marks, not to many though. Do you think that will influence the performance of the lens badly? Is there maybe a way to change the glass with a different filter.
Sooner or later I will get a "snooh" anyway, but that could take a while.

Thanks for your help in advance


Fabian

[John Shriver]

Pretty much equivalent to Y2, K2, or Wratten 8 filter. 10% transmittance (density 1) at about 470 nm.

Leica says (in 1937) a filter factor of 1.6 with Kodak Panatomic film. (Predecessor to Panatomic-X.)

Kodak calls for 1.5 on T-MAX films, but 2 on Tri-X -- see your film data sheet.

Only way to judge the optical effect of the cleaning marks is to take pictures. Summitar Gelbfilter 1's aren't all that rare.

[Rich Silfver]

A #1 should be about half a stop.