305mm repro-claron cells.. compur #2?

[Lightbender]

How dissapointing.. I just received a set of 305mm reporo-claron lens cells..
and they are way to big for a #1 shutter. Perhaps these are an older version.
It appears they fir a something like 45 or 46mm.. perhaps a compur #2?

Argh. Word of warning.

[Emmanuel BIGLER]

Hello from France !

The following dimensions as posted on S.K. Grimes' web site
http://www.skgrimes.com/compur/index.htm

apply to (some) #2 compur shutters and to most old and modern #3 shutters, so you'll easily identify whether your lens actually needs a #2 shutter or bigger.
A metric thread size of M45.75-0.75 for lens cells is quoted by S.K. Grimes for "some of" #2 Compurs. This thread size is very close to your measurement. Actually M45.75 is a very odd size for a metric thread; a pitch of 0.75 mm however is very common and found on many photographic filter mounts. I am not aware of any filter size in M45.75 ; M46x0.75 however is common for photographic filters, there is a reasonable hope that you could screw your M45.75x0.75 lens cells on an empty filter ring of size M46x0.75.
Moreover, the cell thread required for a #3 shutter is M58x0.75, which corresponds to another common filter size. So there are some possibilities to play with standard filter rings or step-up rings, and see what happens; the problem being to get the proper cell spacing. Without a proper spacing, the lens will not perform as it should.

I do have a lens mounted on a Compur #2, it is a 2.8-100 mm Zeiss Planar. After a proper revision, this shutter has been performing flawlessly for 8 years which is very short with respect to the actual life expectancy of a compur ;)
If your lens needs a #2 shutter, and if a combination of standard filter step-up rings is not appropriate, it is technically possible to design dedicated step-up rings that will allow your lens to be mounted on a #3 shutter with the proper thread sizes and proper cell spacing.
However, this solution might not be economically interesting with respect to looking for a used #2 shutter.
I have no idea of the availability of used #2 compurs, but if you find one, it might be worth to have it overhauled, except if some specific parts are broken, compur shutters can be cleaned, lub'ed and adjusted .... not really forever but for decades.
I doubt that there has ever been such an item like a #2 Copal shutter, but who knows ?

[Ole Tjugen]

Dimensions are listed as:
A: Cell thread (all are the same front and rear), all are 40 t.p.i.
B: Flange thread
C: Largest aperture diameter
D: Body diameter
E: Length
F: Mount depth (flange to rear end of shutter).

Data - all dimensions in mm :

Compur 2-X Tube 5/I
Compur 2-X Tube 5/II
Compur 2-X Tube 6/II


2-5/I : A: 45.8 x 40 t.p.i. B: 50 x 29 1/13 t.p.i. C: 35 D: 80.5 E: 35 F: 14.6
2-5/II: A: 45.8 x 40 t.p.i. B: 50 x 29 1/13 t.p.i. C: 35 D: 80.5 E: 25 F: 8.3
2-6/II: A: 49.65 x 40 t.p.i. B: 55.8 x 29 1/13 t.p.i. C: 35 D: 80.5 E: 30.8 F: 12.2


These data are taken directly from the Compur repair manual, as made by Compur-werke. Note that ir really is 40 tpi and not 0.75mm, and the retaining ring thread really is stated as 29 1/13 tpi!

[David Lindquist]

Dimensions are listed as:
A: Cell thread (all are the same front and rear), all are 40 t.p.i.
B: Flange thread
C: Largest aperture diameter
D: Body diameter
E: Length
F: Mount depth (flange to rear end of shutter).

Data - all dimensions in mm :

Compur 2-X Tube 5/I
Compur 2-X Tube 5/II
Compur 2-X Tube 6/II


2-5/I : A: 45.8 x 40 t.p.i. B: 50 x 29 1/13 t.p.i. C: 35 D: 80.5 E: 35 F: 14.6
2-5/II: A: 45.8 x 40 t.p.i. B: 50 x 29 1/13 t.p.i. C: 35 D: 80.5 E: 25 F: 8.3
2-6/II: A: 49.65 x 40 t.p.i. B: 55.8 x 29 1/13 t.p.i. C: 35 D: 80.5 E: 30.8 F: 12.2


These data are taken directly from the Compur repair manual, as made by Compur-werke. Note that ir really is 40 tpi and not 0.75mm, and the retaining ring thread really is stated as 29 1/13 tpi!

Ole, do you (or anyone) have any idea why they used 40 TPI rather than a metric pitch? AND even more mystifying, why did they use as odd a thread as 29 1/13 TPI for the retaining ring?
Just curious. Very curious.
David

[Ole Tjugen]

The thread pitch is a result of the thread cut angle - 50 degrees instead of the more common (now) 60 degrees.

Why they chose to state the pitch in tpi, and especially something as weird as 29 1/13 tpi, is a complete mystery.

[David Lindquist]

The thread pitch is a result of the thread cut angle - 50 degrees instead of the more common (now) 60 degrees.

Why they chose to state the pitch in tpi, and especially something as weird as 29 1/13 tpi, is a complete mystery.

Thank you. Looked at some of my old (circa late 1960's-early to maybe mid 70's) brochures. Found that Rodenstock used 29 1/13 TPI on their 210 mm Ysaron and Schneider used this thread on the 180, 210 and 240 mm Componon as well as the 210 and 300 mm Comparons. All these examples are, of course, barrel mounts.
David

[Paul Ewins]

Post war Schneiders will usually be found in a Compur 2 5/II, as per Ole's dimensions above. The usual donor is the 240/5.6 Symmar (not Symmar-S) which either comes in a Compur 2 or in a Compur/Copal 3 with adapters to the Compur 2 thread size. The adapters don't always come off easily though.

[cyberjunkie]

Post war Schneiders will usually be found in a Compur 2 5/II, as per Ole's dimensions above. The usual donor is the 240/5.6 Symmar (not Symmar-S) which either comes in a Compur 2 or in a Compur/Copal 3 with adapters to the Compur 2 thread size. The adapters don't always come off easily though.

You're right. The most affordable choice for a donor lens is the old convertible Symmar 240mm. Better check before buying, because, as you stated, there are some later examples that were sold in Compur No.3 shutter, with two machined adapters that are glued to the lens cells.
If you need to remove the adapters, some kind of "glue remover" must be left to penetrate the threads for some time. Most of the times it won't be enough: you have to drill two small holes on each adapter, and use a lens spanner to unscrew the adapters.
I found such adapters, well made and probably machined in-house by Schneider, in two flavors: No.2 5/II to No.3, and No.1 to No.3.

There are other lenses that use the same Compur shutter, as the Angulon 165mm, but all are more expensive than the Symmar 240mm (some outrageously more expensive, as the Xenotar 2.8/150mm!!).

For the OP:
i know that it's not a great consolation for you, but i was mislead by Schneider literature as well! I purchased a 305mm Repro Claron in barrel, with the idea to put the cells in a standard No.1 shutter, only to find out that the front and back threads are the same :)
I haven't checked already, but my guess is that the needed shutter is in fact the Compur No.2 5/II.
I have no excuse for that goofy purchase, as i have been warned already! I have another Repro Claron, a 210mm, with similar all-black barrel, that don't comply with the specs provided by the .pdf!
Nevertheless i wanted to try my luck, and lost my bet :(
After my failure, i developed a theory: most of the all-black Repro Clarons use non standard shutters, while the version with aluminium front cell should be a safer bet.
There is a 305mm now on the bay (cells only), which is of the latter version... but i don't think i am going to spend some more money to test my theory. :)
From the picture, the threads of the two cells look different, though. If somebody out there is going to purchase those cells, it would be nice to know if i'm right or wrong, as a guidance for other forum members interested in those fantastic dialytes.
I have used my 210mm, with bellows AND tubes, on my Pentax 67, and the results were super! I don't know why they were discontinued, i think in favor of the Apo Artars, but i found an Ebay vendor who claimed that the Repro Clarons were Schneider-made Red Dot Apo Artars! Bah, sounds a little like a cracked bell to me.

have fun


CJ

[Jim Galli]

There are several #2 Compur shutters. The best solution to get the correct shutter with correct spacing is to find an early Symmar 240 / 420 convertible. Then you'll have 240 305 and 420 in a mini modern casket set.

[cyberjunkie]

Jim, i have the actual proof that your suggestion was a valid one!
But the casket could go much further...
I already had two convertible Symmars of the right focal (240mm). One in Compur No.2 5/II, and the other one in Compur No.3 (with two cup-shaped adapters, either glued or FIRMLY screwed, which allow to mount the same cells in any standard No.3 shutter).
Both versions of Symmar 240mm would be fine. If the No.3 (with adapters) is used, it's very likely that the adapters won't come off easily. Most of the times you have to bore two small holes, and use a pin-shaped lens spanner to unscrew the flanges.

On top of the two Symmar cells, which give 340mm and 420mm FL, the following Repro-Clarons could be used:
210mm (black cells)
305mm " "
355mm (aluminium front cell)

The 355mm with black cells goes in Compound No.3 tube 7.

Other lenses, immediately pre-WWII and early post-war coated examples, could fit the same Compur No.2 shutter.
I recently found that a Meyer Weitwinkel Aristostigmat 160mm, purchased in barrel, can be added to the "casket".
I still have to make a conversion sheet, which gives the adjustments for the aperture values of each lens.
Not the easiest and quickest way to use a lens, but still much better than using a lens cap (and even a Packard).

I hope that my small research with Repro-Claron lens cells will prove useful as future reference for those interested in these very fine repro lenses.

wish you all a merry Christmas

ciao

CJ

[Kevin Crisp]

I did, as suggested, get a reasonably priced convertible Symmar 240 and use the cells in that Compur 2 shutter. Spacing was perfect. The unconverted Symmar aperture scale was exactly one stop off so I just do that mental math when I take the Symmar glass out and use the Repro Claron elements. (You want f:22? Use the scale at f:16)

What I also did was pick up a Repro Claron 355mm and 420mm. With an adapter bushing, I front mount those on the Compur 2, leave the aperture wide open on the shutter, and use the aperture off the two lens. Works great for 5x7.

[Jim Galli]

2 more to fit that shutter. 165mm Anulon f6.8 and 150mm Xenotar f2.8. That would make quite the casket set.

[Doug Webb]

I also have the 305 Repro Claron in all black configuration and successfully mounted it in the 240 5.6 Symmar convertible Compur 2 shutter. I now have added a 165mm 6.8 Angulon purchased in barrel to the set.

I am now interested in figuring out how to use the Angulon as a convertible lens in the shutter. I am assuming that I would use the rear cell alone but I'd like some advice on what apperture I'm looking at wide open something like f15 or f18 maybe? I'm guessing that the front cell is not typically used alone. I have never been able to find a copy of the Schneider brochure that explains the use of the Angulon as a convertible lens.

[Paul Ewins]

The Schneider catalogs of the 1930s listed the 165 Angulon as follows:
front cell fl=345mm, exposure factor 4x
rear cell fl=260mm, exposure factor 2x
both are listed as covering 8x10. The complete lens is listed as covering whole plate at f6.8, 8x10 at f11 and 10x12 at f22.

[cyberjunkie]

2 more to fit that shutter. 165mm Anulon f6.8 and 150mm Xenotar f2.8. That would make quite the casket set.

You are perfectly right, Jim.
Unfortunately it's not super easy to acquire one of the two, in barrel.
Personally i never found a 165mm Angulon in barrel, while i have seen many of shorter focals (i even purchased a 65mm one, which is currently fitted in a nice Prontor No.00 shutter).
The Xenotar 2.8/150mm was sold in barrel, and a couple of them went on Ebay not long ago, but the price was not exactly affordable. Much cheaper than a Xenotar in shutter, though. Xenotars originally made in shutter (with matching diaphragm scale) go for big money these days!

I add one more lens, which i bought in barrel and was then refitted in a Compur No.2 5/II:
305mm G-Claron first version (Dagor-type, chrome barrel)

There are also a couple of Tele-Xenar/Tele-Arton that go in a Compur No.2.
Not the popular Tele-Xenar 5.5/360mm, though. It goes in a Compound No.3.
I purchased a 360mm Tele-Xenar in barrel from the same fellow who sold the Xenotars 2.8/150mm i mentioned. All those barrel lenses came from military surplus, and were originally used for ordnance testing :)


have fun

CJ