[filmscanners] RE: Newish Digital Tech

["Austin Franklin" <austin@darkroom.com>]

Hi David,

> "Paul D. DeRocco" <pderocco@ix.netcom.com>
>
> >>>>>>>>>>>
> No. In a Bayer pattern chip, each site makes use of one third of the
> spectrum, and discards the other two thirds. In the Foveon chip, the other
> two thirds of the light is absorbed and measured in the other two layers.
> Another way of looking at it is that the Bayer pattern requires that each
> pixel be divided into three separate smaller sensors, one for each color
> (50% greeen, 25% red, 25% blue), and the smaller size of each sensor makes
> it capture less light.
> <<<<<<<<<<<<
>
> There's a problem with your logic here. Although the Foveon chip measures
> "all the red", each individual site measuring red measures _the
> same amount
> of red_ as any individual site measuring red in a Bayer sensor.

What about the sensor layers below the top one, and then below that?  There
must be some decrease in transmission (not just due to the top “filter”, but
due to the sensor, material whatever...).  All the Bayer sensors measure
 %100 of the light that particular sensor is filtered for, where the Foveon
gets decreased light to the inner two sensing areas.

Given this (and a few other issues that relate, like accuracy of sensing the
frequency), I would speculate that the Bayer pattern sensor would have
higher color fidelity (with respect to accuracy of color) than the Foveon.

Also, this issue about “%100 of the light” keeps being stated by most
everyone who “champions” the Foveon.  Even if it were true, it’s a matter of
significance.  I do not believe it is a significant issue at all.  People
can claim it is, but no one has yet to make any sense as to why, or shoe
evidence of it being so.  The low light performance of the Foveon is not
very good, in fact.  I believe if it is an issue at all, it is a VERY minor
issue.

Regards,

Austin

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