Archived posting to the Leica Users Group, 2000/08/23

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Subject: Re: [Leica] white dot and metering
From: telyt560@cswebmail.com
Date: 23 Aug 2000 11:27:15 -0700

On Wed, 23 August 2000, "Dan Honemann" wrote:

> 
> Ok, here's a dumb question (so those of you who have low tolerance for dumb
> questions can skip to the next msg now).  The M6 TTL meters off of a white
> dot on the shutter curtain.  Why isn't the dot 18% grey?  Does the meter
> test light reflected off both the white dot and some of the black curtain so
> that the composite represents grey?
> 
> I'm assuming the meter works by comparing the reflected light through the
> lens to the light reflected off the white dot.
> 
> Curious Dan

Dan,

The meter works by measuring how much light falls on the dot.  The dot is white to maximize meter sensetivity, and to localize sensetivity in a limited area.  It's a surrogate for having the meter cell itself in front of the shutter curtain, as in the Leica CL or M5.

Doug Herr
Birdman of Sacramento
http://ourworld.compuserve.com/homepages/telyt
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