At 20:41 2/7/02, Winsor Crosby wrote:
Anyone heard of this?
http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?ViewItem&item=1331309981
Sonnar is the nomenclature for Zeiss telephoto lenses. There is certainly
not one that fast on the Contax web site. There is a 200/2 Aposonnar
though, which weighs 5.8 pounds. :-)
While the formulation may be used today for long lenses, it's Carl Zeiss
name for the formulation, not the length. The formulation dates to the
1930 with the original 6 element, 3 group, 5cm f/2 Sonnar created by Ludwig
Bertele specifically for the Zeiss Ikon Contax I. As was typical of lens
designs then, the initial formulation was tweaked and an additional element
added to make it faster. This created the 7 element, 3 group, 5cm f/1.5
Sonnar in 1932, making it then the *fastest* standard lens in the
world. It was also one of the most complex designs to manufacture properly
requiring very tight tolerances.
[BTW, I have a post-war single-coated 50mm f/1.5 Sonnar and it is without
doubt the highest resolving, highest contrast, flattest field, most flare
resistant, best bokeh lens I own (13 aperture blades with curved edges).]
Today, the original formulation is used as the basis for the 5 element,
four group 40mm f/2.8 Sonnar HFT found on the Rollei 35, and a number of 6
element, 3 group medium telephoto lenses for medium format with medium lens
speed. Other than the Rollei 35 lens, it has been displaced for standard
length by the Planar, a symmetrical design much easier to manufacture in
faster lens speeds. One might wonder why the changes in elements and
groups. It's related to aberration correction; the basic core principles
of its design are common among all of them. Prime lenses such as the
Sonnar often require additional elements for aberration correction as speed
increases.
[Bertele was a lens designer from Ernemann and absorbed into Carl Zeiss
when Zeiss Ikon was formed in 1926 from Ernemann and four other camera
companies to compete with Ernst Leitz.]
Currently, Carl Zeiss makes the following Sonnar prime lenses:
Arri 35mm: 100/1.7 135/1.7
Contax 645: 140/2.8 210/4
Contax N1 (AF): 100/2.8 (Makro)
Contax/Yashica (MF): 85/2.8 135/2.8 180/2.8 200/2
Contax G: 90/2.8
Hasselblad 500 Series: 150/4 250/5.6
Hasselblad 200 Series: 150/2.8
Rollei System 6000: 150/4 250/5.6
(by Rollei Fototechnik under Zeiss license)
-- John
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