Re: [Leica] telyt question

[Henning Wulff <henningw@archiphoto.com>]

At 10:35 AM +0200 4/3/03, animal wrote:
>Hi,recently i noticed some dust on the rear of the lens of  a 560 telyt and
>tried to take the lens apart in order to clean it.
>This is very easy the front has a long thread and you just screw it out of
>the lens tube.
>However between the lens assembly and the rest of the body there is a flat
>about 8 mm wide ring .
>I found that out when i first forgot it on reassembly.
>Whats the purpose of this ring?
>Since it does restrict the range of motion of the lens towards the film does
>it not affect focussing at infinity?
>And what would happen if i just leave it away?
>Thanks
>simon
>

This shim is put into the lens to allow for variations in the actual 
focal length of the achromat lens cell. If, for example a particular 
lens cell had a shorter focal length, the shim would have to be 
smaller to allow infinity focussing. As Doug mentioned, leave the 
shim in to give you the maximum focussing range the lens design 
allows.

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    *            Henning J. Wulff
   /|\      Wulff Photography & Design
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