erobkin@uwc.edu
Date: 09/11/00-11:32:12 AM Z
I pulled the following stuff off the web. Those of you with an interest
in some of the technical sides of photo lenses may find it worth looking at.
It looks like the capability of lenses to capture information is taking
another big step beyond the ability of the CCD/digital duo to record it.
Anyone with additional information about any of this? Is it PR and not
science?
Eugene Robkin
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Canon has announced development of the world's first 'Multi-layer
Diffractive Optical Element'. A prototype Canon EF 400mm f4 DO IS USM
lens incorporating this element will be exhibited at Photokina 2000
(Cologne, 20 to 25 September). A commercial version is expected in the
first half of 2001.
By combining a Multi-Layer Diffractive Optical Element and a refractive
optical element within the same optical system, chromatic aberration,
which adversely affects image quality, can be corrected even more
effectively than with a fluorite element. Also, through minute
adjustments, the diffractive optical element makes possible the same
optical characteristics as a ground and polished aspherical surface,
which effectively corrects for spherical and other aberrations.
Further details are available at
www.canon.com/do-info/index.html
---------------------------------
The following site describes some of the manufacturing techniques that
may be involved in the Cannon design.
http://www.takeuchi.mce.uec.ac.jp/papers/upmm/1999-08e/
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