Archived posting to the Leica Users Group, 1997/07/17

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Subject: Re: Concave Lens Elements (2)
From: "Roger Beamon" <beamon@primenet.com>
Date: Thu, 17 Jul 1997 14:58:31 -0700

On 17 Jul 97,  Erwin Puts wrote:

> According to the official computer prints of Leica it is a completely
> flat front surface. The German language brochure calls the front lens
> "plankonkav" which correctly translates to " plano-concave". The English
> language brochure calls it "concave plane", which is misleading. Maybe Mr
> Eastland has been misled too by this ambiguious translation and to be on
> the save side called it slightly concave. To misquote the famous
> astronomer who stubbornly claimed that the earth is round, I  would now
> exclaim: and still the first side of the front lens  is flat. 

Noticing a couple of dried water or spittle spots on the front element of 
my 35/1.4 ASPH M lens after using it the other day, I, just this morning, 
did what I rarely do. I cleaned it! Using ROR and a microfibre cloth 
it sure does *look and feel* like a concave surface to the pad of your 
index finger or thumb. Noticibly so, as opposed to so little concavity 
that you wouldn't sense it.
- --
Roger Beamon  
       Naturalist & Photographer
       Leica Historical Society Of America
       mailto:beamon@primenet.com
          
           Thought for the day:
       Work is accomplished by those who have
       yet to reach their level of incompetence.