Archived posting to the Leica Users Group, 1996/10/07

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To: leica-users@mejac.palo-alto.ca.us
Subject: Re: Emotive lenses
From: dmorton@cix.compulink.co.uk (David Morton)
Date: Tue, 8 Oct 96 06:08 BST-1
Cc: dmorton@cix.compulink.co.uk

In-Reply-To: <1.5.4.32.19961007024100.00722b50@roanoke.infi.net>
msmall@roanoke.infi.net writes:

> In response to David Morton's lengthy-but-interesting post:
> 
> a)  No one has suggested that there was any great secrecy or 
> exclusivity in
> the Leitz' use of residual aberrations for enhanced optical effect as
> developed by Berek.

In the message to which I was commenting, "Dave" <gannet@cftnet.com> 
wrote: "Are there Secret Black Forest Optical Formulas?  Do they use 
trial and error to get the results they want?" I was merely answering the 
question.
   
> Now that Leitz has moved to MTF/OTF 
> standards, expect their lenses to begin performing a bit more like 
Zeiss > optics.

It is my understanding that Leitz have been using these techniques for 
nearly 30 years.
 
> c)  I doubt if optical scientists spend a lot of time disassembling 
> their
> competitors' products.

I have seen it done, and it is very widely practiced. Physically 
measuring samples of a lens can tell you much about the competition's 
manufacturing tolerances and, *much* more importantly, the optimisation 
algorithms used to translate the design overview which one might publish 
in a technical paper, into a real product capable of mass production.

Such algorithms really do represent the 'family silver' of an optical 
engineering company. Finding the point in the n-dimensional (where N is a 
jolly large number indeed) number space which represents the best 
performance *that you can actually make* and make repeatedly, is a 
phenomenally complex problem.

dmorton@cix.compulink.co.uk      |  "The loss of an old man
david@cassandra.compulink.co.uk  |  is like the destruction
Kilburn, London, England.        |  of a library"