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  1. #61
    georg16nik's Avatar
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    Quote Originally Posted by Diapositivo View Post
    .....Computer-aided design made zoom lenses possible for photographic purposes. Until then they were basically only seen in the motion picture industry or in small movie cameras. "Turrets" or "bifocals" were the alternatives.
    1959 - Voigtländer Zoomar 36-82/2.8 for Bessamatic, Exakta, Contax, Pentax, Kodak mounts.
    Not computer aided, as far as I know.

  2. #62
    Ian Grant's Avatar
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    Quote Originally Posted by David Lyga View Post
    Wiltw quote: "back when computers were not used for lens design"

    My question: What was the year that things changed? Or please give a short continuum of years defining the (sudden or gradual?) 'improvement' in zooms due to computer determination of formula, as opposed to manual determination. My rudimentary guess is the 'late 70s'. - David Lyga
    It's ongoing but accelerates in the 90's and then speeds up in the past 10/12 years. These changes mean both types of wide angle lenses improve, the Cosina made WA's for range finder cameras are outstanding optically.

    I use a 17mm Tamron SP (my second) although I'd buy a 21mm Leitz lens for my M3 if I needed a lens like this for commercial use (with film). I much prefer the 21mm Leitz lenses but would buy a Cosina eqivalent if the budget was too tight however I can't justift it these days as I rarely use 35mm.

    Ian

  3. #63
    AgX
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    David, in Germany the first computers to calculate lens designs were applied in the late 50's.

    However these first applications were rather calculations than designing. As the early computers were more related to what we now call calculators than those selfsustained computers aiding in lens design today.
    Last edited by AgX; 11-19-2012 at 05:43 PM. Click to view previous post history.

  4. #64
    Poisson Du Jour's Avatar
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    Olympus introduced its own optical computational metrics by proprietary computer in mid-1973 and began the task of creating the retro-focus inverted 6E/5G optic of the XA, released in July of 1975. The design of that camera was evidently unorthodox, and the compromises that had to be made to fit a very sharp lens into a small space were formidable for that time (the question asked is, who else did the same thing, eliminating just about all of the sever forms of distortion and aberration, AND which wasn't a fold-out design?), though commonplace today (and often better) in many RFs.
    “The photographer must determine how he wants the finished print to look before he exposes the negative.
    Before releasing the shutter, he must seek 'the flame of recognition,' a sense that the picture would reveal
    the greater mystery of things...more clearly than the eyes see."
    ~Edward Weston, 1922.

  5. #65
    Diapositivo's Avatar
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    I think at the time the designers designed a zoom lens based on intuitions and knowledge/witchcraft, then had to make calculations to verify/understand lens behaviour. With zoom lenses (zoom proper, lenses that perform at all focal lenghts) these calculations take a huge amount of time, considering the great number of lenses and the very great number of "positions" (zoom, focus, aperture), and computer helped make this calculation allowing the designers to figure out much faster at which focal length a problem might have appeared, modifying the design, calculating again etc. This "trial and error" procedure was certainly much faster with computers.
    Fabrizio Ruggeri fine art photography site: http://fabrizio-ruggeri.artistwebsites.com
    Stock images at Imagebroker: http://www.imagebroker.com/#/search/ib_fbr

  6. #66
    Bill Burk's Avatar
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    I used to think of the Pentax Super Takumar 35mm f/2.0 (with 67mm filter ring) as a rectilinear wide angle lens. Was I mistaken? Or is this really an attribute of that lens?

    After it was stolen, I "replaced" it with the Olympus Zuiko 35mm f/2.0 lens. I wasn't thrilled that I was introduced to barrel distortion. So I never really took a liking to that lens, and I kept thinking I should get the shift lens... not at all for the shift feature... but because I had the impression it was bound to be rectilinear.

  7. #67
    lxdude's Avatar
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    Quote Originally Posted by AgX View Post

    However these first applications were rather calculations than designing. As the early computers were more related to what we now call calculators than those selfsustained computers aiding in lens design today.
    A very important distinction. The early computers replaced mathematicians who did calculations manually; they did them much faster and less expensively. This led to more complex designs being attempted, because the calculating power was there to facilitate them; before then they were impractical or unprofitable.

    Later computing power improved to the point that they could support the programming necessary to become design tools.
    Large cost reduction has also come from a reduced need for prototypes.
    Last edited by lxdude; 11-19-2012 at 11:57 PM. Click to view previous post history.
    I do use a digital device in my photographic pursuits when necessary.
    When someone rags on me for using film, I use a middle digit, upraised.

  8. #68
    David Lyga's Avatar
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    Very understandable about the advancement of zoom optics and what I really thought: that this computerization of design was largely gradual, emanating (seminally) from 'helping' to calculate and verify the manual efforts, then gradually segueing into actually BEING the 'person' who formulates the data.

    Might I ask another question: I heard long ago (two decades) that varifocal lenses were actually sharper than zooms because they had to be refocused with each change in focal length. Has the quality of today's zooms negated that 'advantage'? - David Lyga
    Last edited by David Lyga; 11-20-2012 at 08:52 AM. Click to view previous post history.

  9. #69
    Diapositivo's Avatar
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    As a side notation, the best lenses as far as correction of distortion and of field curvature are usually lenses for "reproduction stand" normally to be found in 50mm and 100mm, often called "bellows" lenses because they don't have a focusing helicoid and must be used in conjunction with a bellows (they would normally focus at infinite, with their bellows).
    Fabrizio Ruggeri fine art photography site: http://fabrizio-ruggeri.artistwebsites.com
    Stock images at Imagebroker: http://www.imagebroker.com/#/search/ib_fbr

  10. #70
    AgX
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    In case is true that Parfocal lenses have less abberations, the ability with Varfocal lenses to focus with a long FL and to zoom then back to a short FL, and by this gaining higher focussing acuracy, might compensate in some cases for any better lab-performance of Parfocal lenses.

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