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  1. #41
    Helen B's Avatar
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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

  2. #42
    edz
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    Quote Originally Posted by Biogon Bill

    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.
    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.
    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. :-)
    Edward C. Zimmermann
    BSn R&D // http://www.nonmonotonic.net

  3. #43

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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?
    Claire (Ms Anne Thrope is in the darkroom)

  4. #44
    edz
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    Quote Originally Posted by Claire Senft
    I douby very much that Zeiss has lied.
    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?
    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...
    Edward C. Zimmermann
    BSn R&D // http://www.nonmonotonic.net

  5. #45

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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.
    Claire (Ms Anne Thrope is in the darkroom)

  6. #46

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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?

  7. #47

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    Quote Originally Posted by edz
    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?



    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. :-)
    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.

    http://www.photo.net/bboard/q-and-a-...?msg_id=009t9L

  8. #48

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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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