How different are Tessars from different companies?

[erian]

Has somebody experience with Tessars from different companies?

Are they more or less the same or there are noticeable differences?

[Drew Wiley]

The term Tessar applies to a particular element configuration that has been made by numerous companies for a variety of formats for over a hundred years. So, of course, there are going to be all kinds of variations. The most modern LF tessars are the Nikkor M, preceded by the Nikkor Q and Fuji L series. Then you drift back into names like Xenar and Zeiss Tessar, certain Ektars etc which had long internal evolutions of their own. Different vintages tend to have somewhat different renderings or personalities.

[Mark Sawyer]

The bigger differences come in speeds, dates, and coatings, or lack thereof. In my observations, the super-fast f/3.5s aren't as sharp as the f/8s, even at equivalent f/stops, with others falling in between accordingly. Very early Tessars don't seem quite s sharp as the later ones, though they still perform well, (the same can be said of other lens designs, with the most difference in Petzvals and Dagors). Coatings increase the contrast, of course, and the early coatings are more easily damaged, though that tends to be more cosmetic. I like Tessars, and having a fair sampling, (Zeiss, Wollensak, Ilex, B&L, Kodak, Fuji, Nikon, Lomo, Astragon...) and never found one I didn't like...

And, of course, the reliability and consistency of the shutter should be considered too...

[Jody_S]

Are they more or less the same or there are noticeable differences?

Yes.

[Louis Pacilla]

Yes.

+1

[Mark Sawyer]

Yes, they more or less the same or there are noticeable differences...

[Dan Fromm]

Hmm. Tessars from the same company aren't always the same.

In the beginning, Carl Zeiss Jena made f/4.5 and f/6.3 Tessars. The 6.3ers had usefully more coverage than the 4.5ers. Over time the 4.5ers were recomputed and their coverage grew. And over time CZJ developed faster Tessars, always with less coverage than slower ones. A Tessar isn't a Tessar isn't a Tessar ...

[goamules]

As with many vintage designs, someone decides to remake one, even though there are millions of used ones out there. https://www.kickstarter.com/projects/126995799/create-the-sharpest-colorand-bokeh-miracle-citogra?ref=recommended&ref=discovery

I find it interesting that in 35mm sizes, there are not that many Tessars. In LF, there were plenty.

[Sal Santamaura]

...someone decides to remake one, even though there are millions of used ones out there. https://www.kickstarter.com/projects/126995799/create-the-sharpest-colorand-bokeh-miracle-citogra?ref=recommended&ref=discovery...

"Someone" might have "decided" to remake it, but the outcome wasn't positive:


https://petapixel.com/2018/08/21/how-meyer-optik-gorlitz-won-at-kickstarter-but-failed-at-life/

[Tin Can]

Wow!


"Someone" might have "decided" to remake it, but the outcome wasn't positive:


https://petapixel.com/2018/08/21/how-meyer-optik-gorlitz-won-at-kickstarter-but-failed-at-life/

[Jimi]

Over time the 4.5ers were recomputed and their coverage grew.

When did this happen, is there some way to distinguish the 4.5ers? I have a 1920 Tessar, a 150/4.5, that I have yet to actually test, but I hope it covers 4x5" (or at least 9x12 cm) straight-on.

[Dan Fromm]

As with many vintage designs, someone decides to remake one, even though there are millions of used ones out there. https://www.kickstarter.com/projects/126995799/create-the-sharpest-colorand-bokeh-miracle-citogra?ref=recommended&ref=discovery

I find it interesting that in 35mm sizes, there are not that many Tessars. In LF, there were plenty.

Interesting assertions about sharpness, whatever that means, no MTF or resolution measurements to support them.

[Dan Fromm]

When did this happen, is there some way to distinguish the 4.5ers? I have a 1920 Tessar, a 150/4.5, that I have yet to actually test, but I hope it covers 4x5" (or at least 9x12 cm) straight-on.

Sorry, can't help you. Look for a copy of A Lens Collector's Vade Mecum, which gives some chronology, or, better yet, Hartmut Thiele's Fabrikationsbuchs.

I believe that the various vintages all look much the same.

[John Kasaian]

Greater than usual coverage is the biggest difference that I can see.
Kodak Commercial Ektars have it, while other Tessars don't.

The lyrics were supposed to go:
Mamma don't take my fourteen inch Kodak Commercial Ektar away
but Paul Simon couldn't get it to rhyme :rolleyes:

[Dan Fromm]

Greater than usual coverage is the biggest difference that I can see.
Kodak Commercial Ektars have it, while other Tessars don't

:confused: f/6.3ers have more coverage than f/4.5ers but I'm not aware that Commercial Ektars have more coverage than f/6.3ers.

[mdarnton]

The thing about the run of the mill 4.5 Tessar is that they are sharpest in the center and get gradually unsharp as you move out. Combine that with a wide circle of illumination that lights the film well beyond any sharpness at all and it will be up to you if it covers well enough for you, based on how picky you are at the corners. 6.3 versions are somewhat better in this regard.

For instance, this one is probably marginal for some, but OK for me:
https://www.flickr.com/photos/michaeldarnton/14692136852/in/dateposted-public/
It's asking a lot of a 190mm Tessar formula to cover 5x7.

[Bernice Loui]

Could be related to the innate differences as to how a LF (not press 4x5 camera) -vs- 35mm roll film still image camera would be used.

35mm film camera and it's modern digital equivalent is typically used for "decisive moment" images where the lens ability to capture light, increase shutter speed, brighter image in the view finder to aid in focusing and all related would favor large aperture lens designs like a Gauss. This evolved the typical 35mm lens into a 50mm f1.4 to be common offering.

In the world of LF (not press camera 4x5) Images produced would be more conceived, planned or crafted. Typical LF camera sits on a tripod where shutter speed or exposure time is typically longer than a hand held 35mm camera. This would put the need for large aperture lenses into the lesser importance category with other aspects of lens design primary like image circle and image quality and other aspects of lens design that might not be as significant for a 35mm hand held camera.

As for Tessar lens formulations for LF, they have become favored for most image making (Kodak Ektar due to Lanthium glass and their image results due to the design being "tweaked" by designers and image makers who understood very well what is required for high quality prints. Lens aperture used would be f4.5 to about f22). They are a trade off design like all designs. They do not have the largest aperture, largest image circle and more, but if one were to consider the overall LF image making needs, they are a extremely excellent compromise of the MANY factors and demands for a LF lens design.

There is NO ideal LF lens for ALL image makers, only way to know what specific LF lens works for your print making needs is to try them LOTS.



Bernice





I find it interesting that in 35mm sizes, there are not that many Tessars. In LF, there were plenty.

[mdarnton]

There are plenty of 35mm Tessars, but they are all on cheap cameras, mostly non-interchangable, with 1/10 ‐ 1/200 type shutters for home hobby shooters (Kodak Retina, Ansco Memo, etc.) With 35mm the glass is so small it probably was not a big deal to make a faster lens, earlier.

[Drew Wiley]

Less elements meant less flare, particular in older days. Also less complicated to mfg.

[John Kasaian]

:confused: f/6.3ers have more coverage than f/4.5ers but I'm not aware that Commercial Ektars have more coverage than f/6.3ers.

Interesting. Does it have anything to do with having the more open aperture of 6.3s? But then how would that explain the f9 450 Nikkor M which covers 12x20 with coverage to spare?:confused:

[Drew Wiley]

The whole point of a smaller aperture is that it mechanically vignettes off the lower resolution parts of the image circle. Guess that's why they termed em Commercial Ektars. Portrait studios typically wanted faster aperture, shallower depth of field, and weren't as concerned about corner resolution, so coveted 4.5 versions. Someone else can describe the specific Ektar options better than me; but Zeiss and others had more than one speed/size selection of tessar. I have a Zeiss f/9 360 barrel process tessar that is extremely sharp over its whole image circle, but still renders lovely out of focus background blur. By contrast, my Nikkor M's are thin elements for a tessar design, especially contrasty, being multicoated, but also clinically sharp with the busy annoying background blur typical of Nikon LF lenses, so wonderful for intentionally sharp landscape subjects, but not ideal for anything "dreamy". The 300 M is extremely sharp on 8x10, but with very little to spare, so not really very versatile on this big a piece of film. I mostly enlarge my negs, so a contact printer might have a more liberal definition of usable image circle than I do, as well as at how small a stop detail rendition becomes unacceptable. Probably very few ULF shooters enlarge their negs. And certain applications, like studio portraiture, don't require significant tilts or rises. So it's all relative.

[Dan Fromm]

Interesting. Does it have anything to do with having the more open aperture of 6.3s? But then how would that explain the f9 450 Nikkor M which covers 12x20 with coverage to spare?:confused:

Not at all. The prescriptions are different.

[Drew Wiley]

I suspect even the glass types are significantly different because traditional LF tessar elements are quite thick and heavy relative to diameter, whereas Nikkor M's are rather thin, compact, and lightweight.

[Pere Casals]

I suspect even the glass types are significantly different because traditional LF tessar elements are quite thick and heavy relative to diameter, whereas Nikkor M's are rather thin, compact, and lightweight.


Nikkor M series has no extraordinary glasses, lenses in the nikon range sporting some expensive glass elements are T and AM series.

A 4 elements and 3 groups design cannot correct all well, and some sacrifices are required in one feature or other, I suspect that M design allows some field curvature (like many Tessar designs) to be good in other fetures. This would be painful for architecture, but anyway it lacks and ample circle (around 55º) for that application, so no problem.


I find the M a bit harsh in the Out Of Focus backgrounds, of course it can be used for portraits but one has to be aware about that, because subject isolation is not the same than with a Xenar, for example.

[Drew Wiley]

C'mon, Pere - do you have a spy inside Nikon optical engineering discovering the secrets of their specific glass types per application; or have you gone out, bought a lens, and sent it through a mass spectrometer to identify the elemental composition, or are you merely guessing? Fortunately, I don't need to guess the answer to my own question. Do you even actually shoot these lenses? I certainly haven't detected any field curvature; but at f/9, most of the sloppy part of the image circle has been cropped out for a realistic film format sizing. They aren't specific for apo graphics applications anyway, like process lenses. And they don't have images circles as generous as plasmats or wide field four-element dialytes, and their out of focus rendering is indeed noisy; but in certain other respects, like sharpness and hue rendering, they are exceptional.

[Pere Casals]

C'mon, Pere - do you have a spy inside Nikon optical engineering discovering the secrets of their specific glass types per application; or have you gone out, bought a lens, and sent it through a mass spectrometer to identify the elemental composition, or are you merely guessing?

:) Drew, quite easier... check the nikon catalog, they show off what lenses have special ED glass which is much more expensive and imposes a larger lens. Those elements painted in yellow are the expensive ones. http://www.kennethleegallery.com/pdf/Nikkor_LargeFormatLenses.pdf


"A Tessar comprises four elements in three groups, one positive crown glass element at the front, one negative flint glass element at the center and a negative plano-concave flint glass element cemented with a positive convex crown glass element at the rear."


Tessar is crown and flint, no ED.

M is a great field lightweight lens, but nothing extraordinary, I feel it was expensive for what they gave, so a good product for Nikon.

[Drew Wiley]

Where are you getting that information, Pere? Sure, I've got a copy of Kingslake who describes how tessars were first invented that way long ago. Many many specific glass types have evolved since the crown vs flint option. There are also ways lens element performance can be significantly altered via specific coatings. In this case, a little knowledge is dangerous - another old saying. You know just enough to think you know something you really don't know, and it shows. I have that Nikon LF brochure you linked, and it doesn't indicate the specific glass at all in this case. And as far as high-dispersion glasses go (which aren't necessarily all the same either), they are appropriately chosen when needed, but are not in themselves an indicator of superior quality if a lens can achieve its intended performance using other glass types, which might not be cheap either. You're oversimplifying the entire subject. A real optical engineer might or might not have the answer. Both Nikon and Fuji can be somewhat secretive at times about lens details.

[Mark Sawyer]

There were several types of new glass, including new variations of crown glass created by Otto Schott for Zeiss around 1887 through to 1893 that made anastigmats possible. (The old crown and flint combinations couldn't correct for astigmatism.)

Edited from the Zeiss site regarding the Tessar:

(Referring to the Zeiss Anastigmat/Protar that preceded the Tessar): This was different with the new achromats made from the new types of glass melted by Otto Schott. These new types of glass were known as dense crown glass because they combined a relatively high refractive index with lower color dispersion. The combinations of refractive index and dispersion now available enabled a cemented surface in achromats with a collective effect, which could be used to correct astigmatism. However, with the new achromats, very little could be done to influence the spherical aberrations. Therefore, it was a logical idea to combine both types of achromats with complementing properties to create a lens in which an old achromat was used for the front element and a new achromat for the rear element.

BTW, Zeiss notes about the Tessar:

Simply the advances in glass technology, similar to the time of its birth, enabled performance increases which also demonstrate the potential of the basic idea. From the outside, a Tessar from 1920 looks exactly the same as one from 1965, but the image quality of the newer lens is considerably better.

Lots of history here:

https://lenspire.zeiss.com/photo/app/uploads/2018/04/Article-Tessar-2011-EN.pdf

[Drew Wiley]

And those glass improvements were a century ago, Mark. I got a catalog supplement of optical glass types the other day from just one distributor, and there were about twenty new options added just past year, added to the hundreds already available. I tossed the list because I didn't need it. Now the big push in innovation is for improved laser and machine vision optics. Kingslake ended his account of lenses once things got to the 1960's, simply because traditional tinkering was beginning to be replaced with space age science, followed by computerized design. Many of the old stereotypes no longer applied. But thanks for the fun Zeiss link. Interesting that the tessar design has been used for cell phone lenses; but it doesn't affect me because I don't take pictures with a phone.

[Mark Sawyer]

But thanks for the fun Zeiss link...

Yup, wasted half an hour of my time... :)

[Jim Galli]

Tessar's are pretty interchangeable. Company to company, the characteristics are the same. The differences from an f3.5 to an f4.5 and from f4.5 to f6.3 are greater than any inter-company differences. The difference from non-coated to coated is greater than company to company. We could have some fun with the wine bottle in the bag type competition and shoot a lowly Ilex 8 1/2" next to a vaunted Commercial Ektar 8 1/2" and I defy anyone to actually find some difference.

The same is true of Petzval's. A petzval is a petzval is a petzval. We worry about differences between Tessar's and then we put the dullest things in front of our lenses. I probably have over 200 lenses that can make world class photographs. The problem is the photographer, not the lenses. I have a world class grand piano in my house and can't play it either.

[Drew Wiley]

Words of wisdom spoken by a true soft-focus photographer. There are other perspectives on the question, however. I'd imagine the aliens would know, since they seem to visit the Tonopah area. I wonder how many of them went into town for pizza after their last invasion? I have an upright grand piano which was my Grandmother's wedding present in 1907. True ivory and ebony keys, exquisite swirly walnut elsewhere, with deep deep coats of hand-applied real shellac. A thing of beauty to behold, but now next to impossible to tune. So making good-sounding music might involve more than just the person punching the keys, and it certainly wouldn't involve me!

[Pere Casals]

Both Nikon and Fuji can be somewhat secretive at times about lens details.

Drew, the M is a low performance and low weight lens, compared to a regular plasmat. Let me compare Nikon M 300 vs Nikon W 300:


Speed: W is f/5.6 , M is f/9

Coverage: W is 70º, M is 57º

Circle: W is 420mm , M is 325mm

4x5" Corner performance: W is around 60Lp/mm , M is around 35 Lp/mm

Field: W is well flat, M is a bit curved

W is 6/4 elements/groups , M has 4/3

Weight: W is 1250gr - M is 290gr


The M loses any comparison aganist the W, except weight/size. No doubt that an M can be a more suitable glass for the field because of weight/size, but not because of performance.

An M it is a substanstially lower performer compared with regular plasmat, say a Nikon W, a Sironar N/S or a Symmar-S, no secret.

No alien glass in an M, it is just a well made basic lens optimized for lightweight, rather than for top performance.

[Drew Wiley]

Pere, maybe you're the only person on this forum who thinks M's are "low-performance", maybe on the whole planet, at least among those who actually shoot with these lenses. Where do you come up with this nonsense? They're incredibly sharp, have exceptionally high microtonal contrast, and superb hue differentiation. That's one of the genuine advantages of less air/glass interfaces, though you'll no doubt come up with some second-hand math derived from some half-baked website as faux evidence otherwise. The only area where even the best plasmats exceed is in image circle coverage, and in a few specialized cases, close-up performance. I have such choices routinely available in the same pack, and can judge the result with my own eyes, both on the groundglass, evaluating resultant negs on a lightbox, and in actual print form. I shot a Symmar S 210 for ten years straight, a nice classic lens; but replaced it with a 250 Fuji W/6.7, which was noticeable sharper and better corrected, then a 240 Fuji A Super Plasmat, which was better still, among their deservedly termed "Super Plasmat" series. But the Nikor 200 and 300 M's are right up there, every bit as good as if the film format size is not itself excessive, in fact, even a tad better in microtonality and hue contrast. I even use the 300M as my long lens for roll film backs, and things are as sharp as they get in this application.

[Pere Casals]

Pere, maybe you're the only person on this forum who thinks M's are "low-performance"

The M it is lower performance compared to the Nikon W, which is a better lens, but it weights x4.

Do you really think that a M is a better lens than a W?

[Drew Wiley]

"Better" needs to be defined. So yup, better in terms of the parameters I already described, visibly so. But certainly not better as a bookend, where sheer weight and mass counts. But I have no need for a 300W anything, because my Fuji 360 will outperform it anyway - massive image circle in a lightweight no. 1 shutter, and better corrected than any general purpose plasmat. But a 300 M is even a bit sharper and better color corrected, though scant circle-wise on 8x10 per se. My 305 and 360 Apo Nikkors (graphics barrel lenses) outperform em all, but are less practical, and have miserably busy background blur.

[Pere Casals]

"Better" needs to be defined.

Better coverage angle, better circle, better speed, sharper corners, better field flatness, exactly the same contast and worse weight.

John Sexton used a lot the W 210 (Quiet Light , Listen to the Trees...), but the M 200 folds in his Linhof, and performance difference cannot be seen in a 16x20" print, he says, so he also uses M. Probably you should go to 30" or 40" to notice a difference. In a 20" print even my RB 67 MF camera is totally sharp...

[Drew Wiley]

I've seen some of those prints in person, and it would be hard to detect any difference between any number of modern lenses of similar focal length, especially since Sexton tended to print that tree series rather soft or quiet, just like the title of the book states. Such distinction are more apparent at higher contrast and larger scale. But your mind is made up, and the topic of religion is off limits to the forum, and it seems you belong to some lens religion based on somewhere else in the universe, where light bends differently in the gravitational field of the latest LF rendition of tessar design than it does here on earth.

[BrianShaw]

Tessar's are pretty interchangeable. Company to company, the characteristics are the same. The differences from an f3.5 to an f4.5 and from f4.5 to f6.3 are greater than any inter-company differences. The difference from non-coated to coated is greater than company to company. We could have some fun with the wine bottle in the bag type competition and shoot a lowly Ilex 8 1/2" next to a vaunted Commercial Ektar 8 1/2" and I defy anyone to actually find some difference.

The same is true of Petzval's. A petzval is a petzval is a petzval. We worry about differences between Tessar's and then we put the dullest things in front of our lenses. I probably have over 200 lenses that can make world class photographs. The problem is the photographer, not the lenses. I have a world class grand piano in my house and can't play it either.

... and I’d suggest that a “reverse Tessar” - Radar - is in the same performance camp as a regular Tessar.

[Mark Sawyer]

Sexton's work tends to be 4x5 and enlarged, so there's a whole 'nother lens involved. Just to muddy the waters...

[Drew Wiley]

Enlarged just a bit. But it's a different topic than vintage tessars anyway, which I suspect are coveted more for a certain image look rather than portability or sheer sharpness. The relatively late single-coated Fuji L series was prized by portrait photographers because it was less harsh than certain other options. I use the 300M most frequently as a long lens for 6x9 roll film backs, where it's sharper than even my 300 EDIF P67 lens, which is pretty much the Mercedes Benz of MF telephotos, as good as they get. But it's more at home for 4x5, and usable on 8x10 if movements are distinctly conservative. The 200M is another superb 4x5 lens. I also have a 105/3.5 M, another jewel, but suitable only up to 6x9 format. Having a nearly full selection of Fuji A plasmats also, along with Fuji C dialytes, plus some regular plasmats, I have a good basis for apples to apples comparison. Each lens has its particular reason, though I doubt I'd
have any real issue if I had to thin out the set to a third the number. LF lenses got so darn good while they were still being made, that it's hard to go wrong with any of em, though as I have gotten older the lighter wt ones appeal to me a lot more.

[Bob Salomon]

Sexton's work tends to be 4x5 and enlarged, so there's a whole 'nother lens involved. Just to muddy the waters...

Except he also uses a 57 Super Technika V.

[Drew Wiley]

Well, at the time he was quite fond of the 200M, which has limited coverage on 5X7. The 300M would be excellent for that format, and I recall he liked to travel with that lens too. I've only chatted with him in person a few times, and that was long ago. Doesn't matter; I have my own valid reasons for specific lens preferences, and neither St Ansel nor his immediate cowboy hat disciples have much sway with me. For one thing, I started out as a color printer.

[Mark Sawyer]

Except he also uses a 57 Super Technika V.

"For 99.9% of my work I use a 4x5 view camera." John Sexton

http://www.photovisionmagazine.com/articles/sexton.html

[Jim Galli]

... and I’d suggest that a “reverse Tessar” - Radar - is in the same performance camp as a regular Tessar.

And here I thought that a reverse Tessar was a Petzval ;~'))

[erian]

I learned a lot. Thank you all.

[reddesert]

Interesting. Does it have anything to do with having the more open aperture of 6.3s? But then how would that explain the f9 450 Nikkor M which covers 12x20 with coverage to spare?:confused:

Dan answered this question but I will offer a slightly different phrasing. Lens design involves optimizing some parameters that the designer can control to satisfy a set of constraints. Parameters include glass types, element thicknesses, curvatures, and spacings, for example. When the Tessar was first patented, this optimization was done analytically and by iteratively trying solutions. Kingslake walks through the process for an f/4.5 Tessar in the book "Lens Design Fundamentals." Since the 1960s of course these optimizations can be programmed on computers.

The aperture, desired image quality (minimizing aberrations), and angle of coverage are all constraints. Generally, if one relaxes a constraint, it should be possible to do better on some of the others. Faster systems certainly do have more serious aberrations. Making a Tessar-type design slower aperture appears to allow the designer to increase its coverage.

I don't know enough lens design to understand exactly how. However, in Kingslake's walkthrough of the f/4.5 Tessar, for example, at some point he calculates the off-axis aberrations for 17 degree oblique rays (ie a 34 degree angle of view) and has to introduce some vignetting in order to cut off the oblique rays passing through the outermost edge of the rear group, to keep coma and other aberrations within reasonable limits. Presumably, with a slower lens, he could have allowed more oblique rays (greater field of view) before aberrations became too large.

[Pere Casals]

Making a Tessar-type design slower aperture appears to allow the designer to increase its coverage.

Not only for tessars!!

[Ron (Netherlands)]

My experience is that my (older) 6.3 Tessars provide more crisp images than the later 4.5 Tessars.

[BrianShaw]

And here I thought that a reverse Tessar was a Petzval ;~'))

It’s possible I got the “design” name wrong. I intended to be talking about Tessar derivatives, like the Gundlach Radar that I enjoy using as much as any other Tessar design lens. :)

[Bernice Loui]

Spend some time with this Zeiss publication on Tessar lens design and history. It is a nice illustration of how design evolution happens and the FACT glass types alone does not make or break an given design as glass or plastic or similar refractive material is just one aspect of an overall optic design.

Notable is how aspheric surfaces were used to enhance the overall optical performance of the design for a mobile device camera with a designed image circle of 4mm. Another design requirement for a digital camera used in mobile devices is to incorporate part of the antialiasing filter into the design of the optic making the system more specialized while improving overall system performance. Add software to this system and it's no wonder why mobile device cameras have the level of performance they do today.

The idea of incorporating part of the antialiasing filter into the optic was mentioned to me by a friend who worked on a video camera decades ago when they contracted Angénieux to design and build a video zoom lens specific to this video camera to work with the electronic antialiasing filters in the camera. The resulting image system was excellent.

Point being to believe glass choice or glass type alone IS the determinate factor in the overall performance of any optic and imaging system is absurd.



Bernice






BTW, Zeiss notes about the Tessar:

Simply the advances in glass technology, similar to the time of its birth, enabled performance increases which also demonstrate the potential of the basic idea. From the outside, a Tessar from 1920 looks exactly the same as one from 1965, but the image quality of the newer lens is considerably better.

Lots of history here:

https://lenspire.zeiss.com/photo/app/uploads/2018/04/Article-Tessar-2011-EN.pdf

[Tin Can]

Very interesting Bernice, thank you

[MAubrey]

Spend some time with this Zeiss publication on Tessar lens design and history. It is a nice illustration of how design evolution happens and the FACT glass types alone does not make or break an given design as glass or plastic or similar refractive material is just one aspect of an overall optic design.

Notable is how aspheric surfaces were used to enhance the overall optical performance of the design for a mobile device camera with a designed image circle of 4mm. Another design requirement for a digital camera used in mobile devices is to incorporate part of the antialiasing filter into the design of the optic making the system more specialized while improving overall system performance. Add software to this system and it's no wonder why mobile device cameras have the level of performance they do today.

The idea of incorporating part of the antialiasing filter into the optic was mentioned to me by a friend who worked on a video camera decades ago when they contracted Angénieux to design and build a video zoom lens specific to this video camera to work with the electronic antialiasing filters in the camera. The resulting image system was excellent.

Point being to believe glass choice or glass type alone IS the determinate factor in the overall performance of any optic and imaging system is absurd.



Bernice

Zeiss has another article on this very topic!

https://lenspire.zeiss.com/photo/app/uploads/2018/02/Advanced-Optical-Technologies-Optical-design-of-camera-optics-for-mobile-phones.pdf

[Ron (Netherlands)]

Zeiss has another article on this very topic!

https://lenspire.zeiss.com/photo/app/uploads/2018/02/Advanced-Optical-Technologies-Optical-design-of-camera-optics-for-mobile-phones.pdf

hmm....this isn't about Tessars anymore and IMHO there have not been made any Tessars with aspheric surfaces nor been made of pressed glass.

[MAubrey]

hmm....this isn't about Tessars anymore and IMHO there have not been made any Tessars with aspheric surfaces nor been made of pressed glass.

Correct on both counts!

[Drew Wiley]

Tessars, generically, might very well have been made of molded plastic or hybrid components for modern small amateur camera applications. I'm not going to bother to research that either way, because this discussion is centered around LF applications.