Archived posting to the Leica Users Group, 2002/11/30

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Subject: Re: [Leica] Time-line: focal length in centimeters versus millimeters on projection lenses, Epidiaskop IIIs
From: "Willem-Jan Markerink" <>
Date: Sat, 30 Nov 2002 19:39:55 +0100

On 30 Nov 2002 at 11:14, Nathan Wajsman wrote:

> Hi Willem,
> I am surprised nobody has asked this obvious question: what are you
> going to do with it ???

Adding to my collection of course, why?


As if I had a choice at would have gone to the *crusher*, 
if I hadn't picked it up....8-))
(have seen (heard) that happen a few years ago with 3 units at the 
University of Muenchen, and the same happened a long time ago at the 
University of Muenster (where my 700/3.5 lens came from).

Also, after more careful study of the diaskop mechanism, I now also 
understand why the slides go in horizontally, instead of vertically 
(as with any other (Epi)Diaskop (I have 3 more Diaskop's from the 
late 60's, and one  Epidiaskop from the early 30's))....being 
horizontal, you can push a new slide in (onto a sled-mechism), while 
darkening the previous one; then pull out the previous one, at the 
same time as the new one drops down one stage....very nifty, no white-
out fase on screen, only a blackout-stage.
(have been pondering about an auxiliary dissolve-system on my 
Diaskop's....slide-changing is all manual of course, but that hardly 
matters once the screen doesn't go white or black anymore....4x5" 
slides (or 6x12cm in my case) want to be projected a bit longer than 

Sjeesh....'what are you going to do with it'....of all mailinglists, 
this one would have been the last to expect such a silly rational 
question....I believe even shame and excuses are in order here, young 
man! go wash your mouth!....;))

PS: there are folks who collect similar large cinema-projectors, 
category 'a shed full of them'....and measly me, I have only 

- --                 

Willem-Jan Markerink

      The desire to understand 
is sometimes far less intelligent than
     the inability to understand

[note: 'a-one' & 'en-el'!]

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