"Mark Cassino" <[EMAIL PROTECTED]> wrote:

>I'd assume the camera is programmed to go to CW metering if the aperture 
>ring is not in the "A" position - perhaps matrixed metering is not 
>compatible with stopped down metering?  Just a guess...

Right. In order to use matrix metering the camera needs to know the
lens' maximum aperture AND it's shooting aperture.
The max aperture information comes from the on/off contacts on the lens
mount. The shooting aperture information can be acquired one of two
ways:
* Via an aperture simulator ring (not present on the ist-D or ist-DS) 
* From the lens' digital data contact (not present on K or M lenses)

Modifying the lens only solves the maximum aperture issue, so you're
stuck with centerweighted or spot metering for pre-A lenses.

-- 
Mark Roberts
Photography and writing
www.robertstech.com

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