Archived posting to the Leica Users Group, 2000/05/11

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Subject: Re: [Leica] CLA M Cameras - rangefinder check
From: Rick Dykstra <>
Date: Thu, 11 May 2000 21:16:29 +1000
References: <007a01bfba02$5f5a0820$0fc4ead1@pc>

Bill Larsen wrote:
and it is
> easy to occasionally check the rangefinder yourself.

Yes, easy, but a bit fiddly.  Here's a method I've settled on for
checking focussing accuracy.  It's stopped me sending my M's off for
adjustment. Do not do this to your children.

Remove back and replace bottom.
Mount camera on tripod, attach lens also to be tested, set to widest aperture.
Adjust tripod so camera points to floor. 
Lay an R system focus screen diagonally across the film guides, matte
side down.
Ensure the screen is flush with the inside top and bottom guides.
Place a pin on the floor.
Open the shutter on bulb with a locking cable release.
Focus on the pin looking through the rangefinder.
Check focus on the ground glass with a magnifier or reversed 50, 35 or
even 24mm lens.

If it's way off, check that the ground glass is the right way around. 
If it's the right amount way off, then reversing the screen is gonna
make it look good.  Uh oh. 
Try to use the ground glass part of the screen. The split image or
microprism parts seem to mislead.
Avoid greasing up the ground glass with finger oil. Nose oil is better.
Leica R instructions say to not touch the screen.

By the way, does anyone know a good/safe way to clean finger/nose oil
from a focussing screen? 


Rick (call me Gerard) Dykstra

In reply to: Message from "Bill Larsen" <> (Re: [Leica] CLA M Cameras)