12" Goerz Apo Artar Red Dot filter size?

[Bertha DeCool]

I love this lens, need to get it set up for ND and b&w contrast filters.
I.D. on my gauge tells me it's pretty damn close to 43.5mm. Can anyone confirm this, please?
I'd really rather not have to buy something threaded to see if it fits and what I actually need is a step-up ring.
Just trying to save a coupla bucks and shipping time, thanks in advance.

[Mark Sampson]

I don't think that Goerz lenses were meant to take the (now) standard threaded filters, so the threads on the front of your lens may not correspond to any modern size. BITD you would have bought a push-on filter adapter (with retaining ring) to take unthreaded Series filters. SK Grimes can make you an adapter to take modern threaded filters, or you can search for a vintage push-on adapter. They must still be out there- although I wouldn't begin to know where to look these days. Best of luck!

[Bertha DeCool]

I'm just wondering if a 43.5 fit is a happy co-incidence.

[diversey]

I have a non-Red Dot version of this lens. Former owner glued a 49mm-7 adapter on it.

[senderoaburrido]

Are there marketing or design documents floating around that tell of the dimensions of the front and rear threads? I have a smaller Red Dot Artar and am wondering what adapter I'd need to mount it. My calipers give me a strange measurement in both millimeters and inches, both very odd fractional numbers.

[Dugan]

You might want to check "The List", a great source of info compiled by Dan Fromm, at the very beginning of this sub-forum.
That said, SK Grimes did a great job mounting my 12" RDA into a Copal #1 shutter.

[senderoaburrido]

You might want to check "The List", a great source of info compiled by Dan Fromm, at the very beginning of this sub-forum.
That said, SK Grimes did a great job mounting my 12" RDA into a Copal #1 shutter.

I took a look and unfortunately I cannot find anything relating to the front or rear threads.

The rear thread appears to be just a bit too narrow to be M46.

[Dugan]

Ok, it looks like you are looking for a flange to mount the barrel lens to a lensboard....sorry, mine is long gone.
Maybe try a WTB ad?

[senderoaburrido]

No, I'd like to purchase an adapter to front-mount it to a Copal 3S I have. I'm hoping it's a metric standard, as S.K. Grimes' adapters are a bit outside of my price range.

[Dugan]

Ok, understood.
There's a machinist in Portugal, customphototools.com who might be a possible source.