Archived posting to the Leica Users Group, 2000/04/28

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Subject: Re: [Leica] Re: LET'S SEE NOW...WHICH M-TELEPHOTO TO CHOOSE?
From: John Collier <jbcollier@home.com>
Date: Fri, 28 Apr 2000 07:43:10 -0600

Ah the good old days; one gets a picture of an old optical engineer bent
over their workbench giving the lens element another swipe with the file and
thinking, "That'll fix ya, nasty coma!" To the best of my extremely limited
optical knowledge, Leica has been using computers to test lens designs since
the fifties. I think computers have been a wonderful aid in the testing of
lens designs as the calculation of the light ray tracings is very labour
intensive and just was not feasible to any large extent by manual methods.
The levels of mathematical testing of new lenses has become more and more
intensive as computers have become more powerful thus enabling not only the
best possible correction of traditional designs; but, also the quick testing
of new designs. Theses new ideas about lens design are human generated but
computers allow them to be tested relatively quickly and not require a
company to invest thousands of labour hours ($$$$) to see if they might be
an improvement. To my way of thinking, this has freed the optical geniuses
to be even more creative and experimental in the solution of optical
problems. These are the "golden" days of lens design.

John Collier

> From: "Dan Honemann" <ddh@home.com>
> 
> I wish I could see some side by side prints taken by the CAD- vs.
> Human-designed lenses so I could compare the difference, Jim.  I wonder if
> it would show through in a scanned, digitized image.  Do you know of any
> samples of, say, photos taken with the 75 vs. the 90 apo?