Ektar Suggestions

[Bernice Loui]

Did not know this about the smaller aperture tessars. Still the Commercial Ektar has a very nice out of focus rendition along with smooth tonal rendition and neutral color rendition.

Of the group, my favorites for out of focus rendition at max or near max aperture:


f3.5 Heliar.

f4.5 Ektar

f4.5 Xenar.


It seems lens designers of the past understood the importance of out of focus rendition and did not center their design on everything sharp at small aperture (~f22), hard-high contrast, hard edge sharp, over sized image circle even if light fall off might become a problem. They appeared to have a far more balanced approach to LF lens design than their later LF lens designers (I believe is marketing driven).

One last thing I'll add on Ektars, they were very much hand made individually along with very good quality control gave them an extra edge in performance.



Bernice

That said, I personally have never seen a f/6.3 or a slower tessar as beautiful in its out of focus rendition as the best of the faster ones (to say nothing of the Dagor) - at least if you don't move the tessar's front element (and as the out of focus rendition gets better with such displacement, the sharpness degrades quite a bit). I guess calculating a slow 'highly anastigmatic' tessar with a decent amount of residual spherical aberration for the pictorial beauty of the image is entirely possible but I'm afraid no lens maker ever bothered to produce a tessar like that.

[ridax]

Of the group, my favorites for out of focus rendition at max or near max aperture: f/3.5 Heliar; f/4.5 Ektar; f/4.5 Xenar.

Speaking on the out of focus rendition at max. apertures we really should specify what out of focus zones we are talking about - the background or the foreground. Almost every lens in the world renders the background more or less better then the foreground (though unfortunately there are a lot of lenses that work equally bad in both) if well stopped down, but wide open, different lenses are really different. There are tessars that make better foreground and worse background wide open, and have to be stopped down at least 1 to 1.5 stops to get their best background (and the worst foreground) blur; the f/3.5 and f/4.5 Xenars, the 101mm and 135mm and some other versions of f/4.5 Raptars, and many Ektars, Paragons, Ysarons and Zeiss Tessars are among those. In fact, the vast majority of the tessar and triplet type lenses are like that - thanks to the spherical aberration being negative in the mid- and positive in the outer zones of the lens pupil. With this type of the residual SA, the more the shear amount of the SA left in the lens, the more beautiful the background is stopped down 1 to 1.5 stops, and the worst it is wide open. And for the foreground blur, the opposite is true. So judging such a lens by its background blur wide open should actually mean taking the worst (actually, a pretty technical piece of glass without much pictorial qualities nor 'personality') for the best one.

But there are also tessars with no positive SA at all, and those make nice background and bad foreground blur already wide open; examples of those are 74mm and 127mm f/4.5 Raptars, the old 110mm f/4.5 Zeiss Tessar and some others.

[Peter Yeti]

I'm a bit puzzled by your observations. I only have one 4.5/18cm Zeiss Tessar from around 1923 and it's incredibly sharp at f18. There is not a hint of residual spherical abberation as far as I have seen. Actually, my best modern plasmats (Sinaron S's) have to work very hard to compete regarding sharpness and resolution. What's really poor about this Tessar is the OOF rendition regardless of before or behind focus plane. I always thought that's a well known issue with all Tessars. Are Ektars and Xenars really different (and better) in this respect? Sometimes, when the OOF area has basically no structure or contrast, the Tessar works fine. Otherwise, it often gets unpleasant. By contrast, my Goerz Dagors, my Meyer Helioplan, my Busch Rapid Aplanat always produce nice OOF results.

[ridax]

I'm a bit puzzled by your observations. I only have one 4.5/18cm Zeiss Tessar from around 1923 and it's incredibly sharp at f18. There is not a hint of residual spherical abberation as far as I have seen. Actually, my best modern plasmats (Sinaron S's) have to work very hard to compete regarding sharpness and resolution. What's really poor about this Tessar is the OOF rendition regardless of before or behind focus plane. I always thought that's a well known issue with all Tessars. Are Ektars and Xenars really different (and better) in this respect? Sometimes, when the OOF area has basically no structure or contrast, the Tessar works fine. Otherwise, it often gets unpleasant. By contrast, my Goerz Dagors, my Meyer Helioplan, my Busch Rapid Aplanat always produce nice OOF results.

I don't have the 4.5/18cm Zeiss Tessar at hand now so I can't comment on this particular lens. Generally, individual lenses in one and the same line (series, according to the early terminology) may differ in their out of focus rendition. Most of the old f/4.5 Zeiss Tessars (and in fact, many other tessar type lenses, too) don't have their positive spherical aberration strong enough to make the wide-open foreground blur really good but still strong enough to make the background bad. Those are better used at f/7 or at least f/6.3; at these apertures and approximately up to f/16 or so they have enough of negative SA and thus are good for blurring the background. But surprisingly my uncoated 4,5/8cm Zeiss Tessar rendered the blurred background unpleasant at all of its apertures (though its foreground blur was good wide open). And as I mentioned above, the 4,5/11cm Zeiss Tessar makes the background nice already at f/4.5.

Sample to sample variations may also matter here, though even the oldest Zeiss lenses are not too prone to those. Industars usually aren't either. The post-WWII German lenses are even better in their consistency, as are the Kodak and Wollensak ones. But not all the lens makers are/were that reliable. I bought six identically labeled 4.5/190 Ilex Paragons some day, and no two of them were really identical. The actual focal lengths ranged from 194 mm to 210 mm. The individual lens elements were also very different even in the lenses that as a whole were the most similar to each other. Sharpness wise, I was able to name only 2 of the 6 good enough for my needs, and those two were also quite different (in fact, those surprisingly were the very shortest and the very longest focal length ones). And as for the out of focus rendition, both were fine for the background blur stopped down (at least to f/8 for one lens and to f/5.6 for the other) but the longer one also made nice foreground blur wide open, and the shorter one did not. Those Paragons had no serial numbers on the barrels so they might be of some inferior 'budget' batch that wasn't really representative of the normal quality control with this manufacturer but still I don't think I'd ever buy another Ilex lens.

It's rather hard and risky to make generalizations on the topics like this but still I don't think the f/4.5 Schneiders are very different from the contemporary Zeiss Tessars. As for the Kodak lenses, a lot of them have close to nothing in common to each other despite the identical names used. But if still forced to make a general statement on those, I'd rather say most Ektars tend to be sharper but less beautiful in their out of focus rendition then the other tessar type specimens existing in the world.

At f/18 or f/22 and at smaller apertures, tessar type lenses have virtually no spherical aberration left, and so they no longer produce pleasant background blur. Stopped down that much, they may be said to make both the background and the foreground blur bad or 'neutral' depending on how severe a judge you are and what lenses you compare them to. And if you are used to a Dagor you'd probably be a judge as severe as one can ever get. As I've mentioned in another thread (http://www.largeformatphotography.in...=1#post1025646), f/6.8 (f/7.7 if longer) Dagors still have some negative SA left even at f/32 and f/45. That makes the Dagors unbeaten in their background blur quality at all apertures up to f/10 (but go faster, and the positive SA comes into play ruining the background... but still not improving the foreground enough. So I'd never shoot a f/6.8 Dagor at apertures wider then f/10). Tessars have a much much narrower range of f-stops usable for the better background blur and also fail to make the distant highly defocused background as good as the near one (which is an easy task for Dagors) but these usable tessars' f-stops are faster f-stops so for me, tessars are the way to go with smaller formats where wider apertures are used - and alas for the very long focal lengths in LF, too, as tessars (and celors, which usually have their SA similar to those of the tessars) are not as hard to find and are way more affordable then Dagors (and Protars, some of which are as good out of focus as the f/6.8 and f/7.7 Dagors).

As for the residual astigmatism, it is not influenced by the aperture used but as the depth of field and the depth of focus increase with stopping down, astigmatism also becomes less visible in the actual picture. And when the depth of focus is greater then the astigmatic difference, astigmatism is invisible at all - unless you enlarge the picture greatly enough to reduce the DoF and see the sharpness defects again...

Also, astigmatism does not actually blur the lines that are close to radial or tangential (though it really spoils the ones going at an angle to both of the above); astigmatism just makes the radial lines sharp at one distance from the lens and the tangential ones at another. With small DoF, the human eye often does not object to the phenomena, at least for some of the subjects. The eye just catches the sharp lines here and there and is happy to ignore the unsharp ones (if only those are not defocused in a particularly nasty way). That's why those fast non-anastigmatic lenses of the past still make surprisingly beautiful pictures in portraiture and still life and etc. But then landscapes and especially architecture and certain other subjects are quite another matter.

[Bernice Loui]

ridax, thanks for sharing this insight about Tessars and such. It also explains to a large degree why my preferences for specific LF optics and have avoided many.

There must have been technical reasons why behind the differences in lenses, but this is the first time it was explained this way to me.


Thank you..

Bernice

[Peter Yeti]

I agree, this is very educational, indeed. I never researched the reasons why different lenses render OOF so differently. If I understood this right, you say that the balance between positive and negative residual astigmatism is responsible for this effect. I'm still a little puzzled about this and need to think a bit more about it.

Anyway, from experience I tend to stay away from my Zeiss Tessar when OOF becomes important. That seems along the line what I've read from several others using old Zeiss Tessars. But I love to use this lens for landscape where basically everything is in focus. Fortunately, I have a bunch of other options to choose from when OOF is an integral part of the image concept. My Dagors are prime choice as is the Meyer Helioplan (it's like a Celor). But even my modern plasmats like Sinarons, Sironars, and Symmars often produce nicer OOF than this particular Tessar. I have to mention, though, that I hardly ever shoot wide open. And when I do, the Dargors still take the cake. Anyway, all these lenses have their personal strengths and weaknesses and they can be utilized to great advantage.

But while we're at it: What's the deal with the old Heliars? I read that it's special character is due to residual spherical aberration. I do see a slight similarity with the Dagors, though you say it should be astigmatism with the Dagors. Unfortunately, I cannot compare them myself because I don't have a Heliar. Sorry for the off-topic.

[ridax]

Bernice, thanks a lot for your kind words. I really believe nothing is more practical then a decent theory, and knowing a couple of general principles makes memorizing an enormous number of facts unnecessary... Though practice is unavoidable of course - and really pleasant, too. :)


Peter, it's spherical aberration that I was talking about concerning the out of focus rendition, not astigmatism. (I've adopted the SA abbreviation for the spherical aberration as I've seen this used by other people on this forum. Looks like it's not a good idea to be a lazy typist and use abbreviations instead of the full words!)

As for astigmatism, it mostly affects sharpness - especially of the lines that are neither radial nor tangential. Astigmatism is generally not good for out of focus rendition but its influence on this is small enough to be well masked by the spherical aberration. (In fact, other aberrations are often pretty well masked by the spherical one, at least at wider apertures when the spherical aberration is prominent. Thus, the old Zeiss 2.8/180 Olympia Sonnar, the f/5.6 Convertible Symmars and a lot of other non-apochromatic but wisely constructed fast lenses have certain color fringes (though one has to enlarge the image quite a bit to see those) in the picture taken with the lens stopped down, but those fringes are almost impossible to find in a wide-open-lens image: the chromatic aberration just gets lost under the more powerful spherical and spherochromatic aberrations properly configured by the lens designers.)

I do not have an original Voightlaender Heliar either. I've tried some of them and liked them but I didn't like their prices. My reasoning was, Heliars would not beat my Dagors stopped down, and I want faster lenses for my small format cameras only, and I don't want to spend a lot on those. Heaving 6 glass to air surfaces, Heliars are not as flare resistant as Dagors if uncoated, and coated ones are not cheap at all. Besides, I think the best of tessars and celors are good enough for me when I really have to use something faster then a Dagor. Tessar and celor type lenses are plenty and often cost next to nothing.

Universal Heliars are usually valued higher then the other ones but they are not the only lenses featuring moveable elements; so do longer focus tessar type Velostigmats and some other lenses. Besides, there is enough of very affordable tessar and celor type glass on the market that were not intended for changing their elements' positions but those still can be moved pretty easily (some of my own first-hand data on the really cheap longer focus process lenses like that: http://www.largeformatphotography.in...=1#post1035389).

Speaking of the other makers' heliar type lenses, I must say the Heliar formula does not automatically mean a pictorially good lens at all. Enlarging Ektars of the heliar type are just high quality enlarging lenses hardly usable as taking ones when one wants a picture not only sharp but also visually pleasant. And a number of Mamiya heliar-type taking lenses are far from being great out of focus blur makers either.

[russyoung]

Ridax, thank you very much for your detailed and clear text. I wish you had been around when I was writing my dissertation (2004-2007) - was unable to find anyone at an academic institution in Britain who could answer my optical questions, mostly regarding SA and meniscus lenses. Virtually every PhD I wrote/spoke to was only expert in monochromatic light - lasers - and their applications which had little in common with pictorial photography.

With relatively few words, you have illuminated and clarified much.

Russ Young

[Bernice Loui]

Knowledge well shared deserves a good word of thanks as it can help many along this same journey.

It seem not so long ago when Heliars were common and not expensive at all. During this hey-day, most Heliars in barrel can be had for well under $100 easy. So, that was a chance to try and burn film. While they have smooth OOF rendering at full aperture and stopped down a bit, the majority of them were not coated and were prone to flare. This caused enough contrast reduction for me to pass on so many of them for images made on color film. The one exception was a 210mm f3.5 which appears to be coated and put back together by Burke & James (aka: lens bank). This is the only Heliar that remains in the pile today.

Since those days, I'm simply shocked at the current market price of Heliars, specially the Universal Heliar.



Bernice

Bernice, thanks a lot for your kind words. I really believe nothing is more practical then a decent theory, and knowing a couple of general principles makes memorizing an enormous number of facts unnecessary... Though practice is unavoidable of course - and really pleasant, too.

Universal Heliars are usually valued higher then the other ones but they are not the only lenses featuring moveable elements; so do longer focus tessar type Velostigmats and some other lenses. Besides, there is enough of very affordable tessar and celor type glass on the market that were not intended for changing their elements' positions but those still can be moved pretty easily (some of my own first-hand data on the really cheap longer focus process lenses like that: http://www.largeformatphotography.in...=1#post1035389).

Speaking of the other makers' heliar type lenses, I must say the Heliar formula does not automatically mean a pictorially good lens at all. Enlarging Ektars of the heliar type are just high quality enlarging lenses hardly usable as taking ones when one wants a picture not only sharp but also visually pleasant. And a number of Mamiya heliar-type taking lenses are far from being great out of focus blur makers either.