Three-element lens designs by Zeiss

[CMur12]

I'm aware of the following three-element lens designs by Zeiss, though there may be others:

Triotar, Pantar, and Novar.

I have had a hard time finding any specific information about these lens designs and I would like to know what the formulation of each (probably best shown in a diagram) is and how they compare in optical performance.

I'm of the impression that the Triotar is the best of the three, and diagram of it that I saw somewhat resembled a Tessar, with its rear element similar to the rear doublet group in the Tessar.

Does anyone here have any specific information about these lenses?

Many thanks!

- Murray

 

[JeffL]

I don't have anything specific but I remember reading somewhere that Novar lenses (or some Novar) where made by manufacturers like Rodenstock for Zeiss.

 

[Jerevan]

Zeiss Triotar derives from the Cooke triplet (patented 1893) and at that point it was a major step in managing aberrations in lenses.

 

[Roger Hicks]

Dear Murray,

It is somewhat hard to see how any of them can be anything other than Cooke Triplet types: 3 glasses, 3 groups, outer elements biconvex, central element biconcave. What other choices are there for a 3-glass lens covering a normal field of view?

Cheers,

R.

 

[michaelwj]

Roger,

There can actually be lots of options. For example, each element could have a flat surface and a convex (concave) surface. The only real thing is that each element needs to have an overall positive or negative power to form the mage. The real
The real advances would come from different glass types though.

 

[zuiko85]

Come to that , three element lenses were made by almost all optical makers, often in the lower priced, less well specified cameras. Can't believe there was much difference in performance between them, especially if the angle of view required was similar.

 

[xayraa33]

I remember people in the know at camera shows would avoid the Yashikor equipped used Yashica TLR cameras and go for the Yashinon ones, as the 'kors were Cooke triplets and the 'nons were of a more optically corrected Tessar lens design.

Now a days the reverse would happen, as the majority has gone swirly bokeh crazy, and triplet lens designs tend to give a swirly bokeh in certain conditions and at certain aperture settings.

 

[Roger Hicks]

Roger,

There can actually be lots of options. For example, each element could have a flat surface and a convex (concave) surface. The only real thing is that each element needs to have an overall positive or negative power to form the mage. The real
The real advances would come from different glass types though.

Dear Michael,

Fair enough, though I don't think I've ever encountered triplets with plano-convex outer elements or a plano-concave centre element, and I'd be surprised if any of them were meniscus lenses. I could of course quite easily be wrong.

As you say, the real differences would probably come from glass types, but given that triplet standard lenses are always bottom of the line, I doubt there was much exotic in that department. Even if there were, it would be quite hard to find out. Nor are precise spacings normally specified in commonly available information.

Cheers,

R.

 

[sevo]

I don't have anything specific but I remember reading somewhere that Novar lenses (or some Novar) where made by manufacturers like Rodenstock for Zeiss.

Not quite. As far as I can make out there were no Zeiss (Jena or Opton) marked lenses by third party makers. However, the 1951-52 Zeiss Ikon Nettar II sold in Western Germany was unusual in that it was fabricated in the GDR (Dresden) for Zeiss Ikon Stuttgart, with lenses marked Rodenstock Novar.

I suspect political reasons for that - Zeiss Ikon probably needed a Western lens by Western political demand (or taxation pressure), so no Jena lens could be used, while the Eastern boards and authorities refused any Opton lens, so the compromise of a Western third party maker was used.

 

[Greyscale]

Not quite. As far as I can make out there were no Zeiss (Jena or Opton) marked lenses by third party makers...

The Goerz Frontar achromatic lens was used on the Box Tengor (which I think pre-dated the merge of the two companies), and much later, the Frontar was resurrected on the Ikomatic series of 126-film cameras. The Tengor carried the Goerz brand on the lens, while the Ikomatic was marked Zeiss Ikon on the lens surround. I think that the Ikomatic was the only Zeiss Ikon branded camera to be manufactured by a third-party manufacturer (Bilora).

 

[sevo]

The Goerz Frontar achromatic lens was used on the Box Tengor (which I think pre-dated the merge of the two companies),

The Box Tengor originally was a Goerz camera - and Zeiss merged both the lens and camera divisions of Goerz simultaneously, in 1926.

 

[CMur12]

First of all, thanks for all of the replies.

Why would Zeiss have offered three different three-element lenses? One would think that it would have been simpler and less expensive for them to offer only one, especially if it was a down-market lens.

Thanks again.

- Murray

 

[sevo]

Why would Zeiss have offered three different three-element lenses?

Did they, at the same time, from the same company, from the same division, for the same product class and for more than a limited period of overlap? I do not think so - where I can spot any that existed in parallel, it was either in the shape of old stock, of separate units or the East/West issue.

Do not forget that Zeiss were a conglomerate that merged from more than a dozen camera and lens makers, which always consisted of many formally independent companies (where cameras were concerned, Zeiss, the lens maker and Zeiss Ikon, the camera maker), and split into two independent holdings (with numerous daughters each) in separate countries by the 50s.

There was one major change in triplet design which made it through to the consumers right after WWII - a lanthanum glass element, which improved correction significantly. Most German makers marked that improvement by a new name. And earlier on, most makers had gone on from the purely technical "Anastigmat" (licensed from Cooke) to a fantasy name they could themselves copyright, as the Cooke patents (and their contracts) expired.

Many German makers managed to offer triplets by three names on essentially the same body - not at the same time, but more or less consecutively, with only a few years of overlap. Which tells us that the camera body production (at least for entry level scale focus cameras) moved much slower than their lens designs.

 

[radi(c)al_cam]

I'm aware of the following three-element lens designs by Zeiss, though there may be others:

Triotar, Pantar, and Novar.

[…]

I'm of the impression that the Triotar is the best of the three, and diagram of it that I saw somewhat resembled a Tessar, with its rear element similar to the rear doublet group in the Tessar.

«[T]he Triotar is the best of the three»?

AFAIK, many if not most «Triotar» lenses are interchangeable 80--135mm lenses for 35mm camera, so:

Is it sensible to compare them to say 50mm lenses for a 35mm camera (many «Pantar» lenses, many of them non-interchangeable) on the one hand, and a 75mm lens for a 120/220 camera (many «Novar» lenses, again, many of them non-interchangeable) on the other hand?

If yes, how?

 

[Roger Hicks]

I did slightly wonder about definition and format. The Triotar is after all found in 40mm guise on the Rollei 35s, quite a stretch for a triplet even at f/3.5; the 45mm Pantar was arguably even more stretched, despite the longer focal length, because of its f/2.8 aperture; and Novars were (as far as I am aware) 75mm and 105mm lenses for MF, at f/6.3 and f/4.5. It's quite easy to make an f/6.3 triplet; not too bad at f/4.5; and f/3.5 is pushing your luck. But you don't expect the same resolution on 6x6 as you do on 35mm...

And of course it's MUCH easier to make an adequately sharp lens if the focal length is significantly more than the diagonal. Both Novoflex and Leitz made ultra-long lenses that were just cemented doublets.

Cheers,

R.

 

[radi(c)al_cam]

I did slightly wonder about definition and format. The Triotar is after all found in 40mm guise on the Rollei 35s, quite a stretch for a triplet even at f/3.5; the 45mm Pantar was arguably even more stretched, despite the longer focal length, because of its f/2.8 aperture; […]

You're right of course.
In the late 1960/early 70s, and regarding their 35mm-camera-lenses, I guess, it was more a marketing question than an optical one:
The name «Pantar» became out-of-favour because of its low-budget aftertaste (nevertheless, today the much scolded Icarex COLOR-PANTAR 2,8/50 costs much more than the Icarex Tessar!), and they decided to reactivate the name «Triotar», now for this more-or-less standard length of 40/45mm for Rollei etc.?

 

[sevo]

Is it sensible to compare them to say 50mm lenses for a 35mm camera (many «Pantar» lenses, many of them non-interchangeable) on the one hand, and a 75mm lens for a 120/220 camera (many «Novar» lenses, again, many of them non-interchangeable) on the other hand?

In general, Zeiss branded lenses for marketing reasons rather than from a purely engineering point of view. Two fundamentally different designs were sold as Sonnar, at least three as Biotar, and even Tele- and Apo-Tessars have little in common with Tessar types.

So far, I have found no source that can describe the differences between different Zeiss triplets (other than in focal length and speed) - pictures (even on patent literature) often display some generic triplet type. At the end of the 1920s, Zeiss must have had something like a dozen different triplets, as each maker they had absorbed must have had at least one (I can identify the triplet names Triotar, Nettar, Hypar, Ernon, Triplet and Anastigmat just from the catalogues of the biggest companies merged into Zeiss Jena and Zeiss Ikon).

"Novar" quite obviously is a attempt to bring that into a unified Zeiss Jena naming scheme, and given that almost all triplet-bearing cameras received a Novar around 1929-31, it is quite likely that the designs often were not merged, but merely renamed according to a central nomenclature. Patents are not really helpful either - as the biggest, nastiest technology company of the era, Zeiss took out patents for every minor change plus some, to claim as much turf as possible, and it is hard to tell which of the many patents associated with that Zeiss lens brand actually is in a given lens.

Later, some of the old names reappeared, but I doubt that that was anything other than marketing/branding, as these names did not change in sync with technical revolutions (Zeiss stuck to their old names Novar and Triotar through lanthanum and coatings, when Agfa, Rodenstock and Voigtländer all changed lens names to celebrate these novelties).

Triotar made a reappearance on mid 1930s small format lenses, perhaps to pitch a "new" Zeiss product against the successful Meyer Trioplan. After 1945 the Triotar name did not really make it to the West - there was only a brief production of 85/4 Contax Triotars at Opton (probably as they were already too slow for a up-market rangefinder), and they resurrected it only at the very end of lens mass production (IIRC as a license to Rollei only). But CZJ in the GDR continued making triplets under that name until they took over Meyer as well and relegated lesser lens production to them.

Pantar was no triplet type to start with, but a Goerz brand name for a advanced Wide Double Anastigmat - its name first appeared on Oberkochen 35mm triplet lenses in the fifties, perhaps to bring in associations of a former quality lens from the pool of trademarks owned by Zeiss, Novar being firmly associated with the then already old-fashioned folders and Triotar then perhaps considered unsuitable by being in continuous Jena/GDR use.

 

[Roger Hicks]

In general, Zeiss branded lenses for marketing reasons rather than from a purely engineering point of view. . . . .

Thanks for this post. It all makes sense. Quite often, I warn people not to look for more precision than is available in the neg/pos process, and here we almost certainly have someone looking for more precision than is available in history. As you say, Zeiss publicity material often shows generic triplet drawings/sections, and why, after all, would they do more?

As well as curves, glass types and spacing, quality control may well have been an important difference between two ostensibly similar lenses with different names.

Cheers,

R.

 

[CMur12]

Wow, that's a lot of good information! Thank you to all who contributed.

The only Pantar lens I have actually seen I have in my possession now. It is my mother's old Zeiss Ikon Contaflex 126 from 1968, with a removable 45mm f2.8 Color-Pantar, much like Roger described above. It was more than adequate for the 3.5" x 5" prints my mother put into family photo albums. (Unfortunately, the shutter failed long ago and you can't get batteries or film for it now. It's still a lovely camera to look at, though .)

- Murray

 

[flavio81]

It's quite easy to make an f/6.3 triplet; not too bad at f/4.5; and f/3.5 is pushing your luck. But you don't expect the same resolution on 6x6 as you do on 35mm...

I agree with you more or less: i find f4.5 triplets to be very good, i've had good results (at least in the center) from a 80/3.5 triplet on a Ricoh 6x6 TLR, and i have never ever seen good results from a f2.8 triplet (avoid!!)