This is from an article called "Flare control in multi-coated lenses of the
Seventies",By Dario Bonazza. It has interesting info about SMC. Full text
at:
http://digilander.iol.it/aohc/selart07e.htm
When Asahi Opt. Co. introduced their Super-Multi-Coated Takumar lenses in
1971, there were many different reactions to this announcement. According to
an article authored by Fabio Amodeo and published in September of 1972 by
Photo 13 magazine, Nikon stated that they already employed multi-layer
coatings (up to three or four) on some lens surfaces and Asahi was fooling
photographers, since no more than 5 layers were technically possible. Also
Canon and Leitz said they were developing a similar process, but 7 layers
was far from being credible. To the contrary, Fuji said they were ahead,
since they already had developed their own EBC (electron-beam coating)
technology up to 11 layers, employed on some lenses for movie cameras on
occasion of 1964 Olympic Games. Further in reaction of the Asahi
announcement, Fuji said they were going to use EBC on camera lenses very
soon.
As I already wrote, Asahi didn't invent the multicoating, since they bought
patents from Optical Coatings Laboratories Inc. (OCLI), based in California.
The merit of Asahi Opt. Co. was to understand the importance of
anti-reflective coating, looking for the proper technology, developing their
own industrial process and put it into production at acceptable costs. That
marked a turning point in the evolution of photographic optics, allowing the
development of modern ultrawide-angle and wide-range zoom lenses. With the
growing popularity of zoom lenses and their ever-increasing focal length
extension (needing more and more elements), multicoating became almost as
necessary as glass in order to obtain quality optics.
It is believed that nearly all major lens makers (including Canon, Nikon and
Zeiss) paid royalties to Asahi to make use of some part of the industrial
process for laying thin anti-reflective compounds on glass elements at
acceptable costs. Leica obviously distinguished itself by stating that
multicoating was of little help and reducing the number of elements was
better for flare control. Of course, when Asahi patents on multicoating
expired many years later, they suddenly changed their minds and started
using multicoating like all other manufacturers.
J. John Cohen, M.D., Ph.D.
Department of Immunology, B-184
University of Colorado Medical School
Denver, CO 80262, USA
phone: +1 303 315-8898
fax: +1 303 315-5967
[EMAIL PROTECTED]
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