What ever happened to Copal #2

[DolphinDan]

Hi all,

I apologize for asking what may be a blindingly obvious question, but I have yet to find answer to what happened to Copal #2? We have Copal Lens Shutters in sizes #0, #1, and #3 but no #2. Why not?

Namaste
Daniel

[Kevin Crisp]

I don't know of a Copal 2. There was a Compur 2, used on several different lenses, and suitable for mounting some lenses that never came in it, like the the 305 REPRO Claron. I've not seen a lens after maybe 1970 or so that came in this shutter size.

[drew.saunders]

I have a Schneider Xenar 180/4.5 in a Compur #2. I bought a lensboard in a #1 size and had it bored out by a friend who had a lathe to the right size. SK Grimes has a large list of retaining rings and flanges by size here: http://www.skgrimes.com/products/mou...-stock-flanges
You'll see there are several Compur #2, a Compound that's more or less a "#2 size," but no Copal #2.

[brucep]

And to make it even more odd....compur 2 shutters come in a variety of sizes so you can't even swap retaining rings

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[David Lindquist]

Following on Kevin's comment on when production of the No. 2 Compur (the last version, the rimset) may have ended, there's this. My 1967 Goerz Optical Co. price list shows both the 9 1/2 inch Dagor and the 12 inch Red Dot Artar were available in the No. 2 Compur (or alternatively the No. 3 Acme). The No. 2 Compur is not shown as an option in their 1970 price list.

Looking at some mid-1960's Schneider literature, the 150 mm Xenotar, the 180 mm Xenar, the 240 mm Symmar, the 240 mm Tele-Arton, the 355 mm Repro-Claron and the 165 mm Angulon were supplied in the No. 2 Compur. So just one focal length in each of their lines used the No. 2 (and none of the Super-Angulons or the Tele-Xenars came in the No. 2). So my hunch would be that with relatively lower demand for the No. 2 Compur, it made sense for Compur-Werk to rationalize their production and discontinue this size. I don't know when Copal started making shutters in the Compur pattern; the 1965 Calumet catalogue shows some lenses available in Copals. My hunch, again it's a hunch, is that for similar reasons Copal elected never to offer a No. 2 shutter.
David

[Alan Gales]

There is also a Copal 3s but no Copal 2.

[David Lindquist]

And to add to this most fascinating subject, from a Schneider brochure with a date code of 1970 there is this: The Xenotar, Xenar, Symmar and Tele-Arton lenses formerly supplied in the No. 2 Compur are now instead supplied in the No. 3 Electronic Compur. And while a similar brochure with a 1966 date code shows the No. III, IV and V Compound shutters (as well as the No. 2 Compur), the 1970 brochure has the three Compounds replaced with the No. 3 and No. 5 Electronic Compurs. Lenses formerly supplied in the No. IV Compound are now in the No. 5 Electronic Compur. Neither brochure lists the Angulon or the Repro-Claron.
David

[brandon13]

I think it has to do with the "relative" max opening size of the shutters. If 0,1,?,3 follow a progressive pattern. A copal 2 would have been in between 1 and 3. Someone said that to me once, but it sounds plausible so I'm sticking with it. Makes sense if you are size obsessed?

[Leigh]

There are two critical parameters for a shutter of this type:

1) The spacing between the front and rear cells (and of course their thread specs).

2) The minimum and maximum diameter of the diaphragm opening.

Once you establish those, you need to find lenses that require them.

My guess is there were not enough lenses requiring this size, and most (?all?) of them would fit in a #3.

- Leigh

[EdSawyer]

Actually, you can, they should all be 50mmx0.9mm thread, at least as far as the rimset versions. It is the shutter to have if you want to use a xenotar 150/2.8

And to make it even more odd....compur 2 shutters come in a variety of sizes so you can't even swap retaining rings

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