Docter Wetzlar APO Germinar 240mm F9 Filter thread question

[Dave Tolcher]

I have bought a 240mm F9 APO Germinar lens marked Docter Wetzlar. It is not the W version. Done the internet searches and the filter thread is not that indicated in the reference articles on these lenses (says it should be 40.5mm). It is in a copal 1, has a 37mm push cap. Internal measurement to the threads is between 35 & 36mm, to the internal edge of the barrel (excluding the thread) is 36mm. I speculate that the stepping ring I need is 35.5mm - anyone help ?

Thanks

Dave

[Joe Forks]

well I can't find any reference of a 240/9 with 35.5 filter threads, however, 35.5mm is a spec for filter thread on the 150/9-W, and the 105/4.5 tessar.
I would tend to trust your measurement in this case.

[Dave Tolcher]

Thanks Joe, I can t find any reference either. It was from Mr Cad originally from when the factory closed down.

[Steve Goldstein]

You might ask Arne Croell if he knows anything about it. You can send him a PM through the forum. He's a member and occasionally posts here, but I don't know how often he visits so he might not see your question for some time.

[Arne Croell]

Thanks for bringing that to my attention - the 40.5mm in my tables came from the original Docter leaflets, but I have one myself which I just checked. It is 35.5mm, same as yours, and the cap is 37mm. Apparently a typo or copy/paste problem in the Docter literature, and my fault that I never checked the lens itself - I only checked the weight numbers when I got it. I'll correct it in the table on my web site.

Arne Croell

[Dave Tolcher]

Thanks Arne, slightly relieved as I was worried about the differences esp as it looked the same as the picture in your paper.