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Re: [Rollei] Re: Agfa Lens



- ----- Original Message -----
From: "Roger M. Wiser" <wiserr  >
To: <rollei  
Sent: Thursday, April 17, 2003 5:41 PM
Subject: Re: [Rollei] Re: Agfa Lens


> Thanks Eric - 2 reflections.
>
> Roger
  How did you illuminate it? Two reflections is only one
element. If this is done with the iris and shutter open you
probably should see six reflections since the Agnar is
suppsed to be a slow Triplet. Depending on the curvature of
the surfaces some of the reflections may be hard to see.
This is true for surfaces which are either nearly plane or
are very strong. Looking at the lens from both ends will
help since surfaces which are hard to see from one direction
may be plain from the other.
  Glass-air surfaces of uncoated lenses are very bright and
those of single coated lenses nearly as bright. Multiple
coated lenses are dimmer but all should still be brighter
than cemented surfaces, which can be quite dim.
  This trick works for lenses which are not too complex.
Complex lenses have too many reflections to count
accurately.
- ---
Richard Knoppow
Los Angeles, CA, USA
dickburk  

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