What threaded filters for Rodenstock Heligon?

[bkrystad]

My post-war II has a Rodenstock Heligon lens with threads. Anyone familiar with what size screw-in filter works with it? 28mm? or thereabouts? Anyone know the Kodak filter series name that works? How about a hood?

I've tried using my series VI push-on adapter that works fine with the Schneider Xenon on my IIa, but found it to be too loose to use on the Rodenstock. The protruding portion of the Rodenstock lens has two different diameters front to back, so the "fingers" on the push-on adapter don't apply enough pressure the full distance to stay tight.

The only manual I've found for the Retina II is the American one with info for the Schneider Xenon lens fitted. Not sure if someone else has literature out there for the German-sold Retina that mentions the available accessories. Any clues appreciated!

 

[oscroft]

I've got a IIa with the Heligon, and I got an original Kodak yellow filter with it. The filter is marked "F 1/32". I guessed it might be a 32mm filter, but that appears to be the outside diameter when I measure it. The filter thread measures 29mm to the outside of the thread pitch (as best I can measure it), but I don't know if that is how filter threads are measured - if it is measured to the inside of the thread pitch it is probably 28mm.

I have an original filter booklet, in German. I can't understand a word of it (well, I can understand the word "filter", but you know what I mean 🙂 ). It's just about bedtime here in the UK now, but tomorrow I'll scan it and post it here (together with a pic of the actual filter). I also have the original German manual for the IIa with Heligon, so I can send you a scan of that too. In fact, I'll scan both manuals and put them on the web (though that will have to wait a few days).

 

[Bryce]

If it helps, thread standards are quite old and generally followed. The name diameter of the thread is the maximum allowable size for the crests of the male thread, and the pitch is the distance between crests.
It sounds like Alan's filter is a 29mm thread from his post.
Among the possible ways to solve the problem, since you're in the Seattle area is a visit or call to Kenmore Camera. They have always had a great selection of used filters you could try for fit. At least if you found one the right size you could go shopping.