> My Katz Eye screen is a plain matte fresnel surface without metering
> aids, a custom design for scribed lines.
>
> Yes, I talked with Rachel Katz about the problem I was seeing at
> length. Her take on it is that Pentax reshaped the scatter of the
> screen for the K10D model to provide more brightness at the ocular,
> which has the effect of reducing the amount of light at the metering
> sensors. So they use a different calibration curve for the sensors,
> based on the notion of less light going their way compared to the DS,
> to give accurate metering.
>
> I conjecture that there's an error in the calibration curve used when
> the camera is in the green-button stop-down metering mode. The
> progression of error as the aperture deviates from wide open is
> regular and it seems to me that the problem is an incorrect
> multiplier or lookup table.
>
> Godfrey
>
... or just a variation in the lens? Doesn't the angle of light
coming in depend on not only the aperture, but also the design of the
lens? As such, it's probably only possible to do an "average" correction.
-Cory
--
*************************************************************************
* Cory Papenfuss, Ph.D., PPSEL-IA *
* Electrical Engineering *
* Virginia Polytechnic Institute and State University *
*************************************************************************
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