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Thread: Lens design & glass types

  1. #1
    IanG's Avatar
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    Lens design & glass types

    Around 1931 when Compur redesigned their shutters from Dial-set to Rim-set the glass in some lens designs appear to change is this true ? (This also co-incides roughly with the introduction of more specialist glasses that allow the manufacture of the faster lenses such as the Summar f2).

    I have a number of Tessar's 135mm /150mm and the glass in the pre 1931 models seems quite different to the later versions. The lenses seem to have been re-designed, the newer glass is softer more prone to scratching, cloudiness etc.

    Ian

  2. #2
    All metric sizes to 24x30 Ole Tjugen's Avatar
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    Re: Lens design & glass types

    The Zeiss Tessar was continuously redesigned throughout its century-long production time. So were most other lenses, and the new and improved glasses around 1930 led to many "tweaks" around that time. Just like the introduction of the first special glasses in the 1890's made the anastigmats possible in the first place.

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    Re: Lens design & glass types

    Um, Ole, a while ago in a discussion about f/6.3 CZJ Tessars, Arne Croell told me that the lens' first redesign was in 1912 to improve ease of manufacture, not performance, and its second after the war. The faster Tessars may well have been redesigned more often, but I'm not sure it is safe to generalize about how often or rapidly designers took advantages of new glasses to improve old designs.

    Happy new year,

    Dan

  4. #4
    All metric sizes to 24x30 Ole Tjugen's Avatar
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    Re: Lens design & glass types

    The f:4.5 Tessar in particular is a difficult lens to improve - attempting that is classical exercise in various optics design software packages.

  5. #5
    IanG's Avatar
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    Re: Lens design & glass types

    Dan, I'm after finding any information on this apparent re-design in the early 30's. The glass type appears to change, the cell sizes differ etc.

    It's well known that the design of the Tessar changed after WWII because of the unavailability or shortages of some specialist optical glasses.

    Ian

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    Re: Lens design & glass types

    Ian, I can't predict when Arne Croell will look in here and notice this thread. PM him, he has all of Hartmut Thiele's books on Zeiss products and production.

    FWIW, I have in hand 1912 and 1936 150/6.3 CZJ Tessars and they're the same lens.

  7. #7

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    Re: Lens design & glass types

    Quote Originally Posted by IanG View Post
    Around 1931 when Compur redesigned their shutters from Dial-set to Rim-set ...
    Was it that late? I recall reading (somewhere) that dial-set Compur was last manufactured in 1925. Maybe my recollection is faulty.

  8. #8

    Re: Lens design & glass types

    FROM: 100 Years of Carl Zeiss Tessar®

    Exactly 100 years ago, Carl Zeiss was granted a patent for an invention
    which became the most famous camera lens of all times:
    the Tessar® lens. Until the death of Carl Zeiss,
    the company’s founder, in 1888,
    the firm almost exclusively manufactured
    microscopes with one exception:
    the Abbe refractometer.
    In the early days of the company's
    history, outstanding developments
    were made by Ernst Abbe
    who was first a scientific colleague,
    then a partner and finally
    the founder of the Carl Zeiss
    Foundation, thus increasingly determining
    the fortunes of the
    company. Ernst Abbe was not
    only a scientist, but also an entrepreneur.
    Currency crises occurring
    around 1893 negatively affected
    the export of microscopes which
    induced Abbe to think about
    extending the product line, thus
    reducing the company’s dependence
    on only one product. From
    1888, Ernst Abbe started to diversify
    the product line. Camera lenses
    became a new business division.
    However, Ernst Abbe also
    granted licenses to companies
    outside Zeiss. This procedure
    avoided an abrupt growth of the
    new division at the expense of
    the other divisions. He deliberately
    accepted the disclosure of development
    and manufacturing
    know-how to competitors.
    A few highly talented scientists
    which he had employed played a
    major role in making this strategy a
    success. Paul Rudolph was one of
    these scientists. He is the father of
    some camera lenses which are still
    produced to this very day. He created
    the Anastigmat camera lens which
    was produced from 1890 and renamed
    Protar® in 1900. Paul Rudolph
    designed two further lenses during
    this period, the Planar® lens – produced
    from 1896 – and the Tessar®
    lens which has been produced since
    1902. The name Tessar gives a clear
    indication of the structure of the lens:
    “tessares”, Greek for “four”, indicates
    that the lens consists of four
    lens elements.
    What is the outstanding feature of
    Tessar®? In the early days of photography,
    pictures were taken in black
    and white. Glass plates were the “image
    storage media” used by serious
    photographers. The light sensitivity of
    the emulsions used was so low that
    shutter speed was counted in minutes.
    The preferred lenses at this time
    were two-element systems with a low
    speed and rather modest image quality.
    A few high-speed lenses existed
    with an aperture of about f/3.5 which
    cost more than a saddle-horse, provided
    pictures smaller than a postcard,
    and whose definition was limited
    to the center of the image.
    Paul Rudolph used new types of
    optical glass provided by the Jenaer
    Glaswerk Schott & Genossen: for example,
    glass types with finer grading
    of the refractive indices at a given color
    dispersion. The use of these types
    of glass made it possible to achieve excellent
    color correction, including the
    correction of astigmatism, spherical
    aberration and field curvature in the
    Planar® lens. However, the lenses were
    large and heavy. As anti-reflective technology
    was still unknown at this time,
    the pictures also lacked brilliance.
    Paul Rudolph found an ingenious
    solution to solve some of the prob-
    100 Years of Carl Zeiss Tessar®
    32 Innovation 11, Carl Zeiss, 2002
    Anniversaries
    Fig. 1:
    Dr. Paul Rudolph
    the inventor of the
    Tessar® lens
    Fig. 3:
    4.5 x 6 Sonnet with a 7.5 cm
    Tessar® f/6.3 lens
    Contessa Nettel , Stuttgart,
    1921
    Fig. 2:
    Cutaway of a Tessar® and
    30 cm Tessar f/4.5 lens for
    Ica 13 x 18 cm reflex camera 2
    lems. The Tessar® lens belonging to the
    type of “Triplet lens” was created. The
    design using a dispersive element
    placed between two collective elements
    results in anastigmatic imaging.
    Instead of individual elements, it is
    also possible to use cemented components.
    In this case, the image-side
    component consists of a dispersive
    and a collective element. The lens with
    its initial aperture – “speed” – of f/6.3
    was patented in 1902. The redesign
    performed by Ernst Wandersleb in
    1904 resulted in the Tessar® f/4.5 lens
    which was available from 1907.
    Innovation 11, Carl Zeiss, 2002 33
    This was soon followed by an f/3.5
    version for cinematography and projection.
    In 1908/1909, Ernst Wandersleb
    designed the precursor to the
    convertible lens sets of the Tessar®
    lens with an exchangeable front element.
    Willy Merté’s development resulted
    in the Tessar® f/2.8. lens in
    1932. A year later, the Tele-Tessar®K
    lens (f/6.3/180 mm) with its sensationally
    high speed was introduced for
    the Contax® camera built from 1932.
    A “quantum leap“ in the image contrast
    provided by optical systems resulted
    from the “anti-reflective coating“ invented
    by Alexander Smakula at Carl Zeiss,
    a thin, reflection-reducing, vacuumdeposited
    layer. A patent application
    for this procedure was filed in 1935.
    The Tessar lens was launched on to
    the market in many versions. Highquality
    stereo lens pairs were part of
    the Carl Zeiss product spectrum at an
    early stage. For example, Paul Franke
    and Reinhold Heidecke used precisely
    paired 55 mm Tessar f/4.5 lenses in their
    first Heidoscop stereo camera as early
    as 1920, the year when they founded
    their company which was later to
    achieve world renown as “Rollei-
    Werke Franke & Heidecke”. Worth
    mentioning is also the 500 mm I.R. –
    Tessar® f/5 lens for aerial photography
    in the 30 x 30 cm format. An interesting
    design created in 1951, the Zeiss-
    Ikon Panflex® mirror box, combined
    with the 115 mm Panflex-Tessar®f/3.5
    lens launched in 1953, made it possible
    to use the Contax® viewfinder
    camera like a reflex camera.
    Standard lenses like the current
    45 mm Tessar® T* f/2.8 lens for the
    Contax reflex camera are generally
    achromats featuring correction of
    chromatic longitudinal aberration for
    two wavelengths. This also applies to
    the Tele-Tessar® lenses which became
    available for the 35 mm and the 6 x 6
    cm formats from 1968. The modern
    lenses of the Tele-Tessar® T* type for
    the Contax® and Hasselblad Series
    200 cameras are also achromats. The
    Tele-Tessar® HFT lens is available for
    the Rolleiflex System 6000. T* and
    HFT stand for enhanced transmission
    thanks to multilayer coating.
    Higher demands made on color
    correction are met by apochromatic
    lenses which are corrected for three
    wavelengths. As early as 1923, the
    Apo-Tessar® lens was the most often
    used lens in reproduction photography.
    From 1982, a 500 mm Tele-
    Apotessar® f/8 lens was provided for
    the Hasselblad 550C camera. There
    are now different versions of the Tele-
    Apotessar® T* lens for cameras such
    as Contax®, Contax® 645 Autofocus
    from Yashica and cameras from
    Hasselblad and Rollei.
    The image definition and brilliance
    provided by the Tessar® lens resulted in
    the slogan “the eagle eye of your
    camera” in 1931. The image-side cemented
    component was the original
    from which the “lens logo” was derived
    and used for many decades as a
    trademark of the company. To this day,
    Carl Zeiss has produced about 5 million
    Tessar® lenses for image sizes mea-
    Fig. 4:
    Contax® Aria with a 45 mm
    Tessar f/2.8 lens
    “Star of Vision Award”
    Ahead of the biggest ophthalmic
    exhibition in the USA, the “Vision
    Expo East Award”, pioneering
    achievements in the optical industry
    are awarded prizes. In 2002, the
    panel of specialists presented the Star
    of Vision Award to Carl Zeiss, for
    a trail-blazing invention made in
    1935: the anti-reflective coating of
    optical surfaces developed by
    Prof. Alexander Smakula. Since then,
    the anti-reflective coating has also
    improved the results obtained with
    the Tessar lens as is illustrated by the
    two historic photos taken with and
    without AR coating. It is not unusual
    for pioneering inventions to remain in
    use for a long time, but it is certainly
    not an everyday occurrence for them
    to be honored with an award many
    decades after they have been made.
    suring from half a fingernail to the
    door of a room. All over the world,
    lenses are produced which are based
    on the Tessar® design, some licensed
    by Carl Zeiss. The result: more than
    150 million units sold to this day.
    Note:
    Tessar® is a registered
    trademark
    Dr. Wolfgang Pfeiffer, Aalen
    Kornelius Fleischer, Camera Lens Marketing
    k.fleischer@zeiss.de
    Dr. Dieter Brocksch, Corporate Communications/
    Technical Information
    brocksch@zeiss.de

    Antique & Classic Camera Blog
    www.antiquecameras.net/blog.html

  9. #9
    the Docter is in Arne Croell's Avatar
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    Re: Lens design & glass types

    Quote Originally Posted by Dan Fromm View Post
    Ian, I can't predict when Arne Croell will look in here and notice this thread. PM him, he has all of Hartmut Thiele's books on Zeiss products and production.

    FWIW, I have in hand 1912 and 1936 150/6.3 CZJ Tessars and they're the same lens.
    Well, I saw it pretty late, Dan. Anyway, for most of the f/4.5 versions there was a major redesign in 1927-1929, according to the lists in Thieles book. The 13.5cm one was redesigned 1927 and all lenses manufactured after 1928 used that design; however, the redesign of the 15cm from 1928 did not see production until the 1950's and was still made according to the 1911 design before and during the war. All the longer focal length (18, 21, ...50cm) were redesigned in 1928-29 and mostly manufactured according to that design, but the manufacturing lists occasionally show batches with the old designs in between. Its not absolutely straightforward.

  10. #10
    IanG's Avatar
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    Re: Lens design & glass types

    Quote Originally Posted by Arne Croell View Post
    Well, I saw it pretty late, Dan. Anyway, for most of the f/4.5 versions there was a major redesign in 1927-1929, according to the lists in Thieles book. The 13.5cm one was redesigned 1927 and all lenses manufactured after 1928 used that design; however, the redesign of the 15cm from 1928 did not see production until the 1950's and was still made according to the 1911 design before and during the war. All the longer focal length (18, 21, ...50cm) were redesigned in 1928-29 and mostly manufactured according to that design, but the manufacturing lists occasionally show batches with the old designs in between. Its not absolutely straightforward.
    Thanks Arne.

    For some reason I didn't see your reply until I did a search today. What you've said coincides with what I've observed with my 135mm tessar's.

    The design change must be connected to perhaps triggered by the switch from the dial-set Compur to the new rim-set Compur shutters, but it also seems to be using new types of optical glass.

    I also have a 50's CZ Jena150mm f4.5 Tessar and that's quite different again, both arms of Zeiss had been co-operating closely at that point, despite different nominal ownership they had high hopes of re-joining the disparate halves.

    Post war East German Tessar's (particularly for Rollei's) seem to have a poor reputation usually blamed on slack quality control, but there was no consistent supply of specialist optical glasses and it appears the lens was re-designed on the fly to use whatever specialist glass was available. This is an area that needs researching.

    Back to the point my pre-1928 Tessar's are better lenses compared to my 30's Zeiss lenses, that may well be due to ageing, but my 30's Tessars and Novar are less contrasty than the older Zeiss lenes & far more prone to flare despite being in excellent condition.

    Ian

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