135mm f5.6 Rodenstock Sironar N - any good?

[Bob Salomon]

If they were symmetrical they would also be convertible. None of these: Sironar-N, Sironar-N MC, Apo Sironar-N, Apo Sironar-S, Apo Sironar, Apo Sironar-W, are convertible and non are symmetrical.

If you can find any of the earlier factory brochures on the above lenses they did include a cutaway of at least one lens in each series. Today they only do that with the digital lenses.

[Leigh]

If you can find any of the earlier factory brochures on the above lenses they did include a cutaway of at least one lens in each series.

That's what I was going by. I have a couple of brochures that include the cutaways.

I didn't know anybody made, or even mentioned, convertible lenses any more.
Convertibles require multi-row aperture scales, so it's not just matter of unscrewing one cell.
I thought that was strictly last-century, or the previous.

Perhaps your definition of "symmetrical" and mine differ.
I always thought a lens was symmetrical if the optical designs of the two cells were the same,
although one might be scaled relative to the other.

- Leigh

[Bob Salomon]

We do have a cut-away of a 210mm Apo Sironar-N that we use to take to shows when they were still current. Here is a picture I just took of it.
Couple of very obvious differences when you have it in your hand. First the glass to air spacing between the front and rear is different. The front has a much larger space. Second the rear cemented pair have a very different color then the front pair. Third the front air spaced element is thinner then the rear one. And lastly the front elements are all larger then the rear ones. And the picture is upside down.

[Leigh]

OK. Thanks.

- Leigh

[JBAphoto]

Tessar, and not derived from a Cooke triplet. f/4.5 tessars do well to cover 110% of their focal lengths, and that stopped well down. Symmetry -- or sort of maybe perhaps symmetry -- has nothing to do with coverage.

My understanding is that Rudolph adapted the Cooke Triplet to design his Tessar

I take it that you usually shoot near wide open.

No, I stop down a fair bit for landscapes, unless there is water moving when I go for shutter speed - I don't like misty water, when I want mist I use mist - The lens which surprises me for lack of coverage is my 150 Apo-Lanthar, which I only keep as a spare and that it was the lens that came with its cam with my Technika

John

[Dan Fromm]

My understanding is that Rudolph adapted the Cooke Triplet to design his Tessar

His starting point is generally understood to have been the Protar. See the VM, which isn't always right; it says that Zeiss claimed the Tessar was derived from the Anastigmat (= Protar) and Unar designs. Kingslake, who's sometimes mistaken, but not often, says that it was derived from the Protar. I'd trust Zeiss, who paid for the work and to whom the patent was assigned, over after-the-fact tale spinners. And among the after-the-fact tale spinners, I'd trust Kingslake, who looked things up.

The lens which surprises me for lack of coverage is my 150 Apo-Lanthar, which I only keep as a spare and that it was the lens that came with its cam with my Technika

This doesn't surprise me. It is a Heliar type and they don't have large coverage. See, e.g., www.dioptrique.info for calculated coverage of several heliar types, with prescriptions usually taken from patents.

I've tested most of the standard issue normal lenses for 2x3 Graphics. USAF 1951 target, measured distances, ... The top of the line of those lenses, everyone says, is the 105/3.7 Ektar, a heliar type. It is the most expensive. But it isn't as sharp in the corners, at the same aperture, as a 101/4.5 Ektar, a tessar type.

[rdenney]

To the OP: The APO Sironar-N was a state-of-the-art general lens of the middle focal lengths less than 20 years ago. It would take experience, extreme care, an appropriate subject, and superlative technique to demonstrate any advantage to the newer Sironar-S, in all respects other than coverage. My 210mm Sinaron-S (which is a Sironar-N) is perhaps the newest lens in my bag, and I have collected lenses to make sharp images, not fuzzy ones, for the most part.

And the plasmat design, being an air-spaced Dagor derivative, is a wide-field design with good coverage at this focal length. You won't run out of coverage for most landscapes, though you might with architectural applications and in close-up photography.

Dan is right that both Zeiss and Kingslake insisted that the Tessar was derived from the Zeiss Anastigmat (which Zeiss subsequently branded as the Protar). Kingslake also provides enough back-story to make it compelling. The Sonnar, on the other hand, was indeed derived from a triplet design.

All the large-format plasmats (which include Sironars, Symmars, Fujinon-W, and Nikkor-W) are approximately symmetrical, compared to designs that are not, such as the tessar, Sonnar, several varieties of double-gauss lenses (including the post-war Planar, Xenotar, and Biometar, which were five-element lenses), and any modern telephoto design whether or not reversed to make a wide-angle lens.

They are not quite symmetrical enough to be optimal at 1:1, or to be convertible without reservation from the time when their designs were optimized for longer working distances. Those newer variations, for example, included the Sironar-N and the Symmar-S. But they are symmetrical enough to mostly eliminate geometric distortions and coma, which are artifacts of unsymmetrical lenses that usually require additional elements and sophistication to correct. Eliminating distortion and coma was the point of the symmetry in the first such lenses (the Rapid Rectilinear was one) and is still true for modern plasmats and wide-field designs (like the Super Angulon and the Grandagon). It's what distinguishes the most common modern large-format designs from lenses for reflex cameras, even though the latest examples have given up a bit of symmetry in pursuit of other optimalities. They also have the advantage of being easy to center on a lens board which facilitates movements.

There, I think I've stuck my unwelcome nose into every minor argument topic in this short thread, heh.

Rick "who's work here is done" Denney

[Meekyman]

Thanks everyone who contributed and I must admit I got lost with some of the detailed conversations!

Well, I bought the lens....better hope I get along with the cameras on the introductory workshop otherwise I will have a lens and no camera!!

Cheers

Graham