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Dan Fromm
31-Jan-2018, 15:01
I recently came by a dagor type 150/9 G-Claron and wondered what we collectively know about telling dagor type G-Clarons from plasmat types. There's been disagreement about using a serial number test (what is the last dagor type s/n?) and about the existence of 355/9 dagor types. Here's the answer:

https://1drv.ms/x/s!AggQfcczvHGN0kIjB_63NhzCEsV5 This link is to a spreadsheet that summarizes what I found. It is in the list.

Short form, there are indeed 355/9 dagor types. The usual serial number test (>12,000,000 = plasmat) isn't quite right. Its close but there are dagor types with serial numbers > 12,000,000 and plasmat types with serial numbers < 12,000,000. 11,000,000, as was suggested in some of the posts I read, definitely isn't where the change occurred. And the two types have different front and rear filter threads, focal length for focal length.

When a G-Claron is in hand, the reflections test still works. Four strong, no weak reflections from each cell = plasmat, two strong and two weak, often hard to see, = dagor.

Mark Sampson
31-Jan-2018, 20:37
I used a 1988 (plasmat) 150/9 G-Claron for many years on the job. It excelled at the close-up and copy work I used it for. I wonder if the Dagor-formula G-Claron was replaced because the newer design was better optically, or just less expensive to make? I'd like to know what you think of your new one, once you've tried it out.

Dan Fromm
1-Feb-2018, 04:48
Mark, it will be a little while before I try it out. When I do, I'll try it on 6x12.

I've had three 240/9 dagpr type G-Clarons. All went through acceptance testing on 2x3 before I sold them. All three shot very well on 2x3 at near and far distances.

I've had one 150/9 plasmat type G-Claron. It wasn't as good on 2x3 as either of my 150/9 Klimsch Apo-Ronars so I sold it. Unfortunately my little Klimsches don't conform to the published Apo-Ronar specs, their cells are not direct fits in any known shutter. And although they cover 2x3, they don't cover 6x12, let alone 4x5. Both versions of the 150 cover around 190 mm at f/22 at infinity.

I can only speculate about why Schneider replace the dagor types with plasmat types. Cost to make may have been a reason. And the air space gives the designer another degree of freedom, hence perhaps better corrections.

Greg
1-Feb-2018, 17:30
https://1drv.ms/x/s!AggQfcczvHGN0kIjB_63NhzCEsV5 This link is to a spreadsheet that summarizes what I found. It is in the list.

When a G-Claron is in hand, the reflections test still works. Four strong, no weak reflections from each cell = plasmat, two strong and two weak, often hard to see, = dagor.

So took a close look at my 355mm G-Claron. Serial # is 13XXXXXX. Filter threads on the front are 77mm and 72mm on the rear which should put it into the Dagor type. But looking at the internal reflections, I am 99% sure it's a Plasmat. Was told it was one of the last ones made by Schneider, but have my doubts....

Dan Fromm
1-Feb-2018, 18:48
Greg, thanks very much for checking my work and pushing back when you found a discrepancy. I checked again -- no one should proofread his own work -- and found that I'd misread the catalogs. Shame on me. All corrected now.

Cheers,

Dan

Corran
1-Feb-2018, 19:23
This continues to be a fun subject. I see you linked that thread I made about 305mm GC lenses in your spreadsheet.

I'll mention one interesting thing I learned from that whole thread again now - there appears to be some G-Clarons around the "cutoff" serial numbers that do not follow the catalog in terms of filter threads or barrel/shutter sizes - possibly discrepancies from the changeover in design. Just recently someone posted on the LF Facebook group about a 240mm GC, serial in the 13 million range, that did not conform to the standard Copal #1 sizing. In theory I thought it would be a Plasmat with that serial #, but who knows.

Luis-F-S
1-Feb-2018, 19:37
I have a 270 G-Claron, Ser 10 486 50X. Definitely the Dagor type, two strong reflections clearly visible. One weak one is also visible. I posted this only because I did not see any 270's on the spreadsheet. L

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Corran
1-Feb-2018, 19:59
Luis, do you know roughly what the usable image circle on the 270mm Dagor is? I'm wondering if it covers 8x20 (~550mm), or if the 305mm is the limit on that kind of coverage.

Luis-F-S
2-Feb-2018, 07:10
Luis, do you know roughly what the usable image circle on the 270mm Dagor is? I'm wondering if it covers 8x20 (~550mm), or if the 305mm is the limit on that kind of coverage.

Not really sure, I suspect it would be similar to an 10 3/4" Dagor. It should cover 8x10 fine, probably a little shy of 11x14, but I've not tired it. L

Dan Fromm
2-Feb-2018, 17:00
Thanks, Luis. Added to list.

ridax
8-Feb-2018, 01:53
There's been disagreement about using a serial number test (what is the last dagor type s/n?) and about the existence of 355/9 dagor types. Here's the answer:

https://1drv.ms/x/s!AggQfcczvHGN0kIjB_63NhzCEsV5 This link is to a spreadsheet that summarizes what I found. It is in the list.

Short form, there are indeed 355/9 dagor types.


I own a 355mm Plasmat-type G-Claron, and I would be really delighted to get a Dagor-type one. So I was happy to see the good news that those do exist. But.... That's what I found checking the list:-

(1) " # 10 737 773 yes http://www.largeformatphotography.info/forum/showthread.php?43664-Strange-355mm-f9-G-Claron "

No data at all on that particular lens. Though the thread itself ends with "no one has yet come up with an early one that is not a plasmat".

Should I belive any lens not proved to be a plasmat to be a dagor?
Should I assume a statement that no one has yet come up with an early 355mm G-Claron that is not a plasmat to be a proof that dagor-type 355mm G-Clarons really exist?
Sorry but I'd better not.

(2) " # 10 737 xxx yes http://www.largeformatphotography.info/forum/showthread.php?63200-A-discovery-Dagor-type-G-Claron-s-as-the-ultimate-Casket-Set "

No data at all on that particular lens... NOW. But the thread originally contained pictures that are now gone, and what those pictures were showing was most probably a 355mm Plasmat.


(3) " # 11 708 xxx. yes http://www.largeformatphotography.info/forum/showthread.php?36395-G-Claron-355mm-Dagor-Type/page4 "

proof positive: NO. See message #32:


Jon Wilson 2-Jun-2008:
My 355mm G-claron <...> has 4 strong reflections, i.e., 2 large and 2 smaller ones, but all strong reflections, and thus must be the plasmat. The 355mm's sn11708xxx.


(4) " #11 737 xxx yes http://www.largeformatphotography.info/forum/showthread.php?63200-A-discovery-Dagor-type-G-Claron-s-as-the-ultimate-Casket-Set"

# 11 737 xxx is never mentioned in the thread.
# 10 737 xxx is mentioned; its the same lens mentioned in the thread #63200 above, and again no data at all is published on it.


That's it. After 10 years of the quest, the 2008 statement "no one has yet come up with an early one that is not a plasmat" is still valid. And the list above is the evidence... And no I am not too happy with it. I would be glad if anyone came up with at least ONE 355mm Dagor-type G-Claron.


P.S.: I didn't check the data on shorter focal length G-Clarons because I am not interested in those.
P.P.S.: I'm sorry. Really.

Dan Fromm
8-Feb-2018, 06:35
Ridax, thanks for your comments.

The owners of the two earliest 355s I found posted the serial numbers 10 737 773 and 10 737 xxx.

-773's owner was asked to count reflections, didn't report. I now score it as a "perhaps," thanks for pushing back.

-xxx's owner asserted that it is a dagor type in the first post in the thread without giving a reason why he thought it was and didn't recant after being told how reflection counts differ between the two types.

I scored Thierry Schreiner's 355 as a plasmat.

11 737 xxx was a misread, I've removed it.

Greg
8-Feb-2018, 08:54
150mm G-Claron 11 XXX XXX Dagor
210mm G-Claron 13 XXX XXX Plasmat
305mm G-Claron 14 XXX XXX Plasmat
355mm G-Claron 13 XXX XXX Plasmat
Difference in reflections is obvious on my lenses.

Dan Fromm
8-Feb-2018, 10:03
Thanks, Greg. I've added y'r 150 to the list.

What's most interesting is lenses with serial numbers around the break point and especially 355s. The break point seems to be around 12,000,000.

You and many others don't post complete serial numbers. Since you're here, I'll ask you. Why not post full serial numbers or at least the first five digits?

Drew Wiley
8-Feb-2018, 12:53
Plasmat style G-Clarons replaced not only dagor process lenses, but even the superb taking Dagors made for them by Kern. I was specifically told this by Schneider. The G-plasmat Clarons excelled in almost every measurable parameter - coverage, sharpness, tangential resolution, etc. I would agree with this, though it's almost impossible to excel the contrast and hue purity of a late Kern Dagor (I was shooting mine a few days ago). Dagors are also tricky to precisely make. The symmetrical halves need to be very precisely matched.

Greg
8-Feb-2018, 13:01
You and many others don't post complete serial numbers. Since you're here, I'll ask you. Why not post full serial numbers or at least the first five digits?

Old habit... and I don't remember why or when I started not to post complete serial numbers!
Greg

Luis-F-S
5-Apr-2018, 19:39
Luis, do you know roughly what the usable image circle on the 270mm Dagor is? I'm wondering if it covers 8x20 (~550mm), or if the 305mm is the limit on that kind of coverage.

Not sure about the usable image circle vs. the circle of illumination, but I finally put the 270 G-Claron on the 11x14 and it does not vignette past f/32. Not sure of the image quality at the corners, that's for another day. L