Recognizing dagor type G-Clarons

[Dan Fromm]

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]

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]

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]

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]

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]

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]

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

174318174319174320

[Corran]

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]

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]

Thanks, Luis. Added to list.

[ridax]

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]

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]

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]

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]

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]

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]

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

[Lachlan 717]

For the sake of the database, here’s an 11,000,000 version on eBay:

209959

209960

[mhayashi]

Thanks Dan for sharing your research.
I wondered if the dagor type weight is different from the plasmat type weight,
just simply comparing the front & rear barrel weights of the dagor type against those of the plasmat type.

If you have an experience with both a gorez gold dot dagor and a dagor type g-claron, how do they differ in pictures?

[Dan Fromm]

Thanks for the kind word.

Comparing weights never occurred to me. I just looked at the catalogs, which don't show weights. One would have to get examples of all focal lengths of both types and and weigh them. I'm sorry, but I don't need that many G-Clarons.

No experience with real (Goerz or CZJ) Dagors of any vintage. I'm sure that they and Schneider dagor types (early Symmars, early G-Clarons) have different engraving and liveries.

[Jody_S]

After looking over Dan's list (thanks!) I wonder if the switch to plasmat type was due to the cost of manufacturing. A dagor requires 3 (usually) equally-sized elements that need to be ground to perfectly match for the glass/glass interfaces. I'll assume that at the time Schneider was doing the final adjustments by hand grinding. Which would be why the first focal length they switched to a plasmat was the largest, the 355, which by virtue of having the largest glass elements would be the hardest to grind to a perfect fit.

And once the plasmat 355 was out there and accepted by the industry, they made the decision to switch the rest of the line too, because plasmats were increasingly used in process lenses starting about then perhaps due to the work Schneider themselves did in perfecting the design for the needs of graphic arts and printing.

[Dan Fromm]

Jody, the G-Clarons are very roughly parallel to Symmars. The original Symmars were dagor types, replaced in the 1950s by plasmat types. The VM says that the plasmat types were better corrected than the dagor types. There's a hint.

[Jody_S]

Jody, the G-Clarons are very roughly parallel to Symmars. The original Symmars were dagor types, replaced in the 1950s by plasmat types. The VM says that the plasmat types were better corrected than the dagor types. There's a hint.

I thought the Symmars converted to Plasmats much sooner? They're rare as hen's teeth, but fleabay almost always has dagor-type G-Clarons. And Schneider obviously knew photographers loved dagor rendering, given how long they kept making 'premium' dagors with fancy marketing (into the 1980s?).

[neil poulsen]

Would a Dagor type G-Claron 355mm have any advantage over a Plasmat 355mm G-Claron? The latter is an outstanding lens.

Do the Dagor type G-Clarons exhibit focus shift, like some of the longer Dagors?

[Corran]

Probably image circle for one. My 305mm GC Dagor covers 8x20, as I've mentioned in the past. The 355 covers 12x20 at the least...maybe more?

PS: my 305 exhibits negligible focus shift. A 210mm f/6.8 Symmar I have of the Dagor persuasion has copious amounts though.

[Greg]

Would a Dagor type G-Claron 355mm have any advantage over a Plasmat 355mm G-Claron?

I believe that I have used both over the years. Am 90% sure that my first 355mm was a Dagor formula. About 15? years later acquired a 355mm Plasmat. Never used both at the same time to compare, but both served me well on my 11x14. Looking at negatives side by side from both lenses (unfortunately different images/images and 15? years apart), I honestly couldn't tell you which was shot with which lens. I can remember only once when the Plasmat wouldn't cover the whole negative... Architectural vertical shot with extreme rise of the front standard.

[Dan Fromm]

Re Dagors' and clones' focus shift on stopping down. My dagor type G-Clarons (150, 210 and 3 240s that I've sold) have/had none. My Boyer Beryls (85, 90, 135, 180, 210, 210 S and 250) have none. My 45/9 CZJ Goerz Dagor (a wide angle lens) doesn't have it either. But I don't doubt that older Goerz Dagors do. Don't know about newer ones, there have been recomputations.

[Drew Wiley]

My experience is with the final Kern dagors that Schneider marketed. The double-triple G-Claron was already in the rear view mirror. They distinctly told me that dagors in general were too tricky to make due to the need for precisely matched front and rear elements, and that the newer GC plasmats were better corrected anyway. Dagors have their own special rendering, but I'm of the impression that GC dagors were marketed as process lenses. Plasmat GC's have much larger effective image circles, and even though marketed for tabletop photography, are superb at infinity too. My Kern Dagors had focus shift only within the first half-stop from wide open.

[John Layton]

When I first got into 11x14 years ago...my first lens was a 19" Eastman Anastigmat (in barrel)...followed by a 14" Schneider/Kern Dagor - which was blazingly sharp but exhibited a noticeable field curvature for that film size. I ended up with a Schneider/Kern Blue-Dot Trigor, from the very last batch, which was absolutely phenomenal in every way.

Edit: Actually, after the 19" E.K. Anastigmat (but before the Kern Dagor)...I did own a 12" Series 3 Dagor for awhile...which covered 11x14 and was quite a nice lens - but there was just a bit of focus shift as I remember.

[Dan Fromm]

Plasmat GC's have much larger effective image circles,

If you believe claims in the catalogs, its the other way 'round.

G-Claron claimed coverage @f/22 (mm)

f dagor plasmat

150 191 189
210 280.5 260
240 319 298
270 360 335
305 411.5 381
355 ? 444

[Jody_S]

They distinctly told me that dagors in general were too tricky to make due to the need for precisely matched front and rear elements, and that the newer GC plasmats were better corrected anyway.

That would explain it. The needs of a process lens are different from a taking lens, different enough to make manufacture of a symmetrical lens a little tricky. So they did likely start with the 355 for cost reasons, being the largest it would have been the hardest to adjust.

[Drew Wiley]

Dan - you have to understand the manner in which their specs were geared to their own idea of intended market application. Because the G-Claron line was repro-application derived, they followed that same kind of extremely conservative image circle basis even when the plasmat GC's were issued. At least that's how my old official spec sheets did it. The actual Schneider sales people tried to re-explain it for regular photographers. There were also wide-angle GC's, which further complicates this. All kinds of people on this forum, especially the ULF gang, know that real-world general photography image circles for the plasmat versions are MUCH larger than the published circles. In other words, they used a different standard for GC plasmats than from their regular plasmat series. With GC spec sheets you also get 1:1 circles, as well as infinity circles.
One problem with dagors is that they aren't as crisp at angled extremes or tangential specs. Repro applications aren't concerned with that because the application is head-on flat field. Tabletop and general usage is, because strong tilts are often involved. I could cite several other factors; but this should be enough to make one scratch their head and begin to understand the seeming anomaly in the specs. It all makes sense if one realizes which trade they had in mind when they published those specs - and it wasn't us!

[Salmo22]

An extremely enjoyable and educational thread. I'm glad I found it and appreciate everyone's contributions.

I have three G-Claron lenses. A 150/9 and two 210/9's. All three show four strong, no weak, reflections. Interestingly, one of the 210/9 GC's has the SN (12 178 XXX) on the front element. The other 210/9 GC has the SN (14 401 XXX) engraved on the rear element. They both accept my Heliopan 77/49 filter step-up ring. The SN (14 555 XXX) for my 150/9 GC is on the rear element. Based upon the information I have available to me, I've assumed my GC's are all plasmats. Please correct me if you think they are dagor's.

[Luis-F-S]

Dagor GC’s should show 2 strong and 2 weak reflections per side. From the serial #s I’d say yours are plasmats

[Dan Fromm]

An extremely enjoyable and educational thread. I'm glad I found it and appreciate everyone's contributions.

I have three G-Claron lenses. A 150/9 and two 210/9's. All three show four strong, no weak, reflections. Interestingly, one of the 210/9 GC's has the SN (12 178 XXX) on the front element. The other 210/9 GC has the SN (14 401 XXX) engraved on the rear element. They both accept my Heliopan 77/49 filter step-up ring. The SN (14 555 XXX) for my 150/9 GC is on the rear element. Based upon the information I have available to me, I've assumed my GC's are all plasmats. Please correct me if you think they are dagor's.

Weak reflections can be hard to see. A plasmat cell consists of two groups, a cemented doublet and a singlet. The singlet faces the diaphragm. The outer group is cemented, makes two strong reflections and one weak. The singlet makes two more strong reflections.

A Dagor cell is a cemented triplet, has two air-glass interfaces, each of which makes a strong reflection, and two glass-cement-glass interfaces, each of which makes a weak reflection.

210/9 dagor type G-Clarons have 40.5 mm filter threads, 210/9 plasmat types have 49 mm.

Your lenses are plasmats.

[Greg Y]

The Dagor G Claron 210 is a knockout of a lens & my favourite (caused me to part with my gold rim 8 1/4." I've never had a G Claron of either type that wasn't a gem.

[Paolo Rimini]

Hello! This is my first post and I was looking for a 210mm dagor for my 8x10. Today I got this copy from ebay. For me it's a dagor. How do you see these reflections? Tread filter 40,5mm lenght 41mm 220407 220408

[Dan Fromm]

Hello! This is my first post and I was looking for a 210mm dagor for my 8x10. Today I got this copy from ebay. For me it's a dagor. How do you see these reflections? Tread filter 40,5mm lenght 41mm

Look at a single cell. Either will do because they're identical. Unscrew a cell from the barrel and use a point source of light.

The cells are direct fits in a #1 shutter.

[Paolo Rimini]

Hi Dan, Thanks. I cannot unscrew the cell but they are identical. It's a barrel lens. I want to try it with Sinar automatic shutter. In a second moment I will put it in a copal shutter, if I will be positively surprised.

[Jody_S]

Hello! This is my first post and I was looking for a 210mm dagor for my 8x10. Today I got this copy from ebay. For me it's a dagor. How do you see these reflections? Tread filter 40,5mm lenght 41mm 220407 220408

It certainly has the barrel shape of the early Dagor-style G-Clarons. The later Plasmat ones tended to have the same style of barrel as their newer Componons.

[Greg Y]

It certainly has the barrel shape of the early Dagor-style G-Clarons. The later Plasmat ones tended to have the same style of barrel as their newer Componons.

The Dagor style G Claron 210 has the 40.5mm filter size. The plasmat style is 49mm. It took me a long time to find one.....but it's a great lens.