Recognizing dagor type G-Clarons

[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