carl zeiss lenses

Claire Senft

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But I am not a benchracer. And I would like to know. As far as photodo is concerned, I too have my problem with them. The MTF grading is optimized for a 4x6 print. I am not much interested in making 4x6 prints. Things I see in their favor: They are a Hasselblad distributor but when one looks at the Rollei tests they have given the highest marks to a Schneider lens. When it comes to the highest score ever given out is was given to a Canon lens. They have several very nice articles to read...good for the grumpy, bed ridden person, as well as others to read.

So JJ can you tell us which abberations do not influence MTF tests or did you perchance misspeak or you are ingnorant of which they are?
 

David A. Goldfarb

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I think JJ and Ed Zimmerman's point is not that there are aberrations that don't influence MTF, but that aberrations that produce a lower MTF value might produce a better image for reasons apart from sharpness, contrast, and resolution. One might reasonably prefer a lens with a lower photodo score over a lens with a higher score.
 

jjstafford

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Claire Senft said:
So JJ can you tell us which abberations do not influence MTF tests or did you perchance misspeak or you are ingnorant of which they are?
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I had answered your question before you asked the second time. See below. Is it not clear that I won't be provoked into benchracing bull?
 

Claire Senft

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OK I am going to give it a rest. Having made your purchase the die is cast and it is up to you how well it is used. To my way of thinking the only abberation not influencing MTF is distortion and that is listed seperately. In addition to that field illumination is also important.

Unless as a result of damage or of a faulty lens slipping thru the system one is fortunate because almost any lens made in the last 30 years is quite a marvelous instrument.

If one wants to be a fanatic abiut lens quality, in my opinion, they should do it with enlarging lenses because that is the most important lens you are likely to own.

Please, no remarks about CZ enlarging lenses.
 

jjstafford

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Claire Senft said:
[...]
If one wants to be a fanatic abiut lens quality, in my opinion, they should do it with enlarging lenses because that is the most important lens you are likely to own.
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Uh oh! Here come the ULF contact printers!
 

Ole

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jjstafford said:
Uh oh! Here come the ULF contact printers!
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So far LF only, but ULF is approaching... But I enlarge LF too! A little while ago I enlared 35mm negatives for the first time in several years. I had entirely forgotten how small they were, and how grainy, and all that!

But a good enlarger lens is an absolute requirement, and not where you should save money. I have (big) Rodagons and (small) Meopta Anaret S'es.
 

David A. Goldfarb

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I like all sorts of exotic old lenses, but I agree with the idea of using the best enlarging lenses, if one must enlarge. I use 50mm and 90mm Apo-Rodagons and a 150mm Apo-Componon HM. I don't think I would be able to afford them, though, if there were still much of a market for enlarging lenses.

On the other hand, I know people who like diffusion at the enlarging stage and enlarge with lenses not really made for enlarging. Wollensak even made a Verito for enlarging.
 

edz

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David A. Goldfarb said:
I like all sorts of exotic old lenses, but I agree with the idea of using the best enlarging lenses, if one must enlarge.
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Enlarging too, I think, is part of the artistic process. In general, however, the best (whatever that means) objectives as part of an appropriate optical system are what should always be selected. Intentional soft-focus, distortion etc. don't typically work well in enlarging. The problem is, however, what "best" means since its tied in very much with the choice of illumination. I find myself, for example, switching between cold light to point source--- and quite a few combinations in between--- depending upon what I'm trying to do. I have, however, also a few "special purpose" objectives that I use for "special effects" such as a zoom (Schneider Betavaron).
 

Biogon Bill

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To clear up a few points . . .

MTF testing is not irrelevant. If it were, lens makers, including Leica, wouldn't be using it. It's a tool. Like any other tool, it has its limits & like any other tool, it must be used appropriately to be of any value. It's certainly true that MTF tests are not the last word in the assessment of any given lens, but to say that it is irrelevant is absurd.

Those uncorrected aberrations that we may love so much in certain older lenses weren't put there by the lensmakers to cater to the needs of the artiste. They are there because it was the best the lens maker could do at that stage of optical development. The goal of the lens maker is the most accurate possible 2-dimensional representation of reality - distortion & aberration free. This is evidenced by their continuing effort to improve on old lenses by the use of aspherics, etc. They make no effort to continue to produce those old lenses with their classic look. Of course, the photographer may have a liking for a certain look & may love to use certain older lenses.

Photodo is not now nor was it ever a distributor of Hasselblad or anything else, as was claimed above. In fact, Photodo doesn't even exist any more. It was an independent testing company, founded by some former employees of Hasselblad, which is a whole different matter.

Zeiss marketing does not claim specifications that violate the laws of optics. As far as I know, they do list specifications that are beyond the capability of the human eye to see. But that is another matter. The information about their specs & resolving power is available if you care to write to them or to the tester who developed the data. It's all available for you to critique.

The 35 mm lens for the Contax G, which has been criticized by some users, is a Planar. For the new M-mount series of Zeiss lenses, Carl Zeiss has substituted a Biogon, which is drawing rave reviews by users.
 

David A. Goldfarb

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Biogon Bill said:
Those uncorrected aberrations that we may love so much in certain older lenses weren't put there by the lensmakers to cater to the needs of the artiste.
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True except for soft focus lenses, in which those uncorrected aberrations were put there precisely to cater to the needs of the artiste.
 

Claire Senft

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There is no problem saying shift lens to me. I have a 35mm PC Distagon and a 28mm Schneider PC Super Angulon from a Leica R adapted to contax/yashica mount both of which I use on my Contax RTSIII.

Why do you suppose there would be a problem in saying shift lens to Zeissaholics?
 

Tom Hoskinson

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It sounds so...Shifty.
 

Helen B

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Alan,

Various mounts are available for the 28 mm Schneider PC Super Angulon (all but the Leica mount from Schneider, the Leica mount from Leica) and they can be switched by removing four screws. It's a great lens.

Best,
Helen
 

edz

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Nope. They selected and tuned aberations as compromise for effect. Have a look at the wide range of special purpose "designer" and portrait objectives one had back in the early part of the last century. If it was about the "best" and "best" was objective then why should a vendor (beyond cost considerations) have ever offered such a wide selection? Why would one have ever given a thought on selection when one could just chose the best?

Zeiss marketing does not claim specifications that violate the laws of optics. As far as I know, they do list specifications that are beyond the capability of the human eye to see.
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They violate the laws of physics in that they claim to have tested the resolving power of a camera optical system using a film ("Gigabit" which is Agfa Copex): Camera Lens News Issue 20 of Sept. 2004, "Gigabit is not a Hoax".
In the article they claim they measured 400 lp/mm on Agfa Copex using ZM objectives in a real camera system. This is not possible. This is complete hogwash when one considers that this claim is even being made for pictorial tonality/contrast (the point of the Gigabit developer) with a film that can't even in "ideal laboratory conditions" resolve 400 lp/mm (and we are not talking yet about objectives, cameras and optical systems).

Erwin Puts did a good intro write-up on this: Zeiss and resolution and fairy tales (October 15, 2004).

Looking through the 20 issues of that "magazine" I've found many marketing claims that push the laws of physics to support Zeiss marketing. I like some Zeiss products but their marketing is these days no better than... Seems like they hired their copy from writers that don't know the difference between nm, mw and ml.
 

Claire Senft

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I do not know the capabilities of gigabite films. I do know that at an aperture of 2.8 a diffraction limit for medium green light would be approx. 560lpm, with blue light this would be in the area of 700lpm.

I douby very much that Zeiss has lied.

Can you offer proof that they have done so?
 

edz

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Claire Senft said:
I douby very much that Zeiss has lied.
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Are we talking religion or science? Are fairy tales lies or just nice stories that people want to hear?

Can you offer proof that they have done so?
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How can one record in an optical system 400 lp/mm on film that is "only" capable of, at best, 250-300 lp/mm? What they have done in the article is to manipulate truth and add smoke and mirrors to dazzle the untrained deep pocket geek (pretending to understand the jingo) into a wannabe consumer.

In reading the article I would say that they don't "exactly" lie but set things up for the reader to draw incorrect conclusions and to then lie to themselves about how great Zeiss is...
 

Claire Senft

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Well Ed as I am sure you know Lipmann type emulsions are capable, according to John B. Williams, in his book Image Clarity, of resolutions up to 2000lpm. I do not think Lipmann emulsions are particularly useful for general photography and a lens aperture of .7 to 1.0 that is diffraction limited would be required to accomplish this and is best afforded by someone such as the NSA with support from Claire and Ed.

But what do I care? My equipment is what it is and as I said to begin with has satisfied my expectations completely.

Also important is the quality of the camera. I have found my device to be satasfactory. Most photographers are only going to be able to judge the optic's quality besed upon looking at negatives, slides and prints. I have many things I wish to purchase and an optical bench or the ability to do MTF is not even on the list.

In judging a lens that will be used with regularity just as important as the optical quality is the mechanical durability of the device.

There again the quality has been satisfactory.

I bet both of us have better things to do than to engage in "Zeiss is good...Zeiss is not so good."

Do you doubt that Zeiss lenses are capable of producing first class results?

I do not doubt that other brands are capable of doing so.
 

jjstafford

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Maybe I'm a poor reader, but did Zeiss say anywere in the paper that they actually MADE the claimed resolution on film? Or did they just posit possibilities?
 

Biogon Bill

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Hi, Ed -

I think that we are largely in agreement about lenses from 50 - 100 years ago. Knowing that lenses with uncorrected aberrations were the best that they could do at the time, lens makers offered lenses with different "looks", i.e. different degrees of corrections of different aberrations. These compromises were the best way of meeting the varying needs of different photographers who were using lenses for a wide variety of purposes. However, the goals of the lens makers remained the same: as accurate a 2-dimensional representation of reality as they could achieve. With aspherics, computer-assisted-design, newer coatings, etc they have come closer to achieving this today. Erwin Putts, whom you quote elsewhere, makes exactly this point in his writings.

Regarding Zeiss marketing claims, I agree that the Zeiss marketing Dept. has been over the top. But I do not agree that their claims "violate the laws of physics." Rather, they seem to have stressed technical qualities of their lenses that will not make much difference to the vast majority of photographers. So, I don't want to defend their marketing decisions. However, the claim of 400 lpm was explored on photo.net 9 months ago. Surprisingly, Kornelius J. Fleischer, the man who did the testing, posted on this discussion & explained his claims. He also addressed Erwin's criticism. You can read his post at the link provided below & make up your own mind on this one. I, for one, am convinced that in this case, Erwin got it wrong & is not the expert of choice here.

www.photo.net/bboard/q-and-a-fetch-msg?msg_id=009t9L
 

jjstafford

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Biogon Bill "With aspherics, computer-assisted-design, newer coatings, etc they have come closer to achieving this today."

Which brings up a question: What lenses manufactured before computers became cost-effective for most (1975?) have not been improved by computer assisted design and proofing?

Was not the Biogon, specifically the second generation (Biogon 38mm) one?
 
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