How to mount a Goerz Artar 10 3/4 inch in a shutter?

[senderoaburrido]

My back up option if all of this is too costly is to simply buy a variable ND filter so that I can reduce exposure times to a few seconds for manual “lens cap over the lens” method. Does anyone know the filter thread and pitch of this particular Artar?


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I have exactly the same lens and am attempting to front-mount it to a Copal 3S. I'll include here pictures of the caliper measurement for the rear thread, and the front.
Curious sizes on both ends. Not sure if lenses of this era had metric threading with imperial focal lengths.

[Dugan]

customphototools.com is the website of the machinist in Portugal.

[PunkFunkDunk]

I have exactly the same lens and am attempting to front-mount it to a Copal 3S. I'll include here pictures of the caliper measurement for the rear thread, and the front.
Curious sizes on both ends. Not sure if lenses of this era had metric threading with imperial focal lengths.

Thanks for the measurements. As it turns out I purchased a cheap 39mm lens hood with standard 0.75 pitch thread to see if it would fit the front of this lens. That way I would know for certain that a modern ND filter of the same size would fit. Alas, it is close but it does not fit. My guess is that the front lens thread is approximately 40mm in diameter and likely has an older threads per inch thread. Hence my plan to use a ND filter will not work. But thanks anyway.


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[senderoaburrido]

Now that I've looked at it many times over, I am almost certain that it is some now-uncommon (by way of most camera equipment post 60's being metric in dimensions) imperial threading. Another guy here managed to gently force a 40mm filter to fit. If there was any difficulty at all, it's likely not 40mm. I'm thinking about getting a thread measurement tool to investigate, however I'd need to have some idea of the angle of the threads to begin with. Each kit is targeted for a 5 degree range.

[Steve Goldstein]

Regarding post #8 (front filter size), on a hunch I just checked my very late (s/n 828xxx) 10-3/4" RDA in barrel. It accepts a 40mm (not 40.5!) filter, same as my 8-1/4 RDA s/n 816xxx. This unusual size was used on some Canon LTM lenses and I don't know what else.

A few months ago I purchased a 40-49 step-up ring from SRB Photographic in England for my 8-1/4, I'll probably get another just to have it for my 10-3/4.

Physical sizes seem to have changed over the years - the 40mm step-up is slightly too large for an older (s/n 762xxx) 10-3/4 RDA I tried. I'll try a 39mm filter if I ever happen upon one.

[senderoaburrido]

Regarding post #8 (front filter size), on a hunch I just checked my very late (s/n 828xxx) 10-3/4" RDA in barrel. It accepts a 40mm (not 40.5!) filter, same as my 8-1/4 RDA s/n 816xxx. This unusual size was used on some Canon LTM lenses and I don't know what else.

A few months ago I purchased a 40-49 step-up ring from SRB Photographic in England for my 8-1/4, I'll probably get another just to have it for my 10-3/4.

Physical sizes seem to have changed over the years - the 40mm step-up is slightly too large for an older (s/n 762xxx) 10-3/4 RDA I tried. I'll try a 39mm filter if I ever happen upon one.

You're certain it threads smoothly? Mine is also in the 800,000 range; 808xxx. The front thread is damaged. Now you're making me wonder if the rear thread is also metric. I sent some measurements to Rafcamera and he seems to think it's M45.5x1. I'm not sure what to think on that front, I'd prefer to measure it myself somehow.

[Steve Goldstein]

You're certain it threads smoothly?

Yes, like a hot knife through butter on both my 8-1/4 and my 10-3/4, like any other filter on any other lens with undamaged threads. It screws in all the way with no change in force throughout its travel.

[senderoaburrido]

Then I suppose that this implies the rear thread is also metric.

[Steve Goldstein]

Hard to say. I just measured across the outside of the mounting threads with a vernier and got 1.785” (45.34mm). I don’t have a proper thread measurement tool but the pitch appears very close to 1mm.

[Joseph Kashi]

My Goerz America 10 3/4" RD Artar came mounted in a Compur 1 MX shutter. I don't know whether this was a factory mount, but it fits neatly and compactly, FWIW.