Archived posting to the Leica Users Group, 1998/03/03

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Subject: Re: [Leica] Leica-Users List Digest V2 #207
From: dmorton@journalist.co.uk (David Morton)
Date: Tue, 3 Mar 1998 19:58 +0000 (PST)

Christian Becker wrote:

> While I was playing around with the cameras, I tried
> metering off a computer screen displaying a peice of email (black
> lettering
> on white background).  What happened was strange.  The M6 showed both
> LEDs
> (i.e. proper exposure) at 1/8 sec at ALL APERATURES from f4 to f11!!!
> Try
> it and you'll see what I mean.  Something in the design of the M6's
> meter
> renders it totally useless for metering CRTs!!
>
> possible reason:
>
> the M6 meter measures light reflecting from the white spot painted
> (painted?) onto the shutter curtain. Does this lead to light
> polarization?

I haven't got an M6 (yet), but I would have thought it more likely that
the metering system was sampled ( to achieve what used to be called
'chopper stabilisation'), and this is the sampling frequency beating with
the CRT vertical refresh. But not having seen it, it's hard to be sure.


            David Morton  |  Please don't tell my mother I'm a journalist,
dmorton@journalist.co.uk  |  She thinks I have a respectable job playing
     (+44) 171 272 8908   |  the piano in a brothel.