Archived posting to the Leica Users Group, 2002/09/29

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Subject: Re: [Leica] Pradovit Color model numbers
From: John Nebel <nebel@csdco.com>
Date: Sun, 29 Sep 2002 07:23:24 -0600 (MDT)

On Sun, 29 Sep 2002, John and Catherine Allen wrote:

> 
> I've looked inside the one I just bought, and I can't see any sign of an
> autofocus mechanism, but I'd like to ask - can anyone explain what a
> Pradovit autofocus mechanism looks like? I believed - possibly wrongly -
> that some kind of reflective beam (infra-red?) was bounced off the front
> surface of the slide, and that there was feedback from this to the lens
> focusing motor which moved the lens in or out by a small amount to keep
> the lens to slide distance constant.
> 
> If this is correct, presumably a Pradovit with autofocus will have a small
> extra gadget somewhere near the slide. What should I look for?
> 
> John
> 
> --
> 
> John and Catherine Allen
> Bofferdange, Luxembourg
> allen@vo.lu
> http://www2.vo.lu/homepages/allen
> 
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> To unsubscribe, see http://mejac.palo-alto.ca.us/leica-users/unsub.html
> 

John,

As one looks at the front of the projector with the cover off, there is a
light source on the left side of the lens aimed at the slide and a
photoreceptor in a shroud on the right, both at a 45 degree angle.  There
is a circuit card mounted vertically to the right of the lens to which the
photoreceptor is wired.

John Nebel 

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Replies: Reply from "John and Catherine Allen" <allen@vo.lu> (Re: [Leica] Pradovit Color model numbers)