Digital BW, The Print

Photosensors don't have to worry about that, ordinary light isn't coherent 
and the wavelengths are out of step anyway.

Yes, lenses focus each colour to a slightly different point. This is called 
chromatic aberration, and camera lenses are designed to minimise it as far as 
they can given cost constraints. This is one of the reasons why camera lenses 
are much more complex than spectacle lenses!

Apochromatic lenses are called that because they are designed to bring the 
three primary colours into focus at the same point, and hence all the other 
colours. Ordinary non-apo camera lenses only concentrate on two colours, so 
have slightly more chromatic aberration.

While I suppose that the physically different positions of the three colour 
pixels in a Foveon sensor might introduce a new form of aberration it is 
unlikely to be very large in magnitude.

As for depth of focus, we're only talking a few microns difference in depth 
between the sensors, that won't be visible. 

On Monday 11 Feb 2002 6:23 pm, Todd Flashner wrote:
> on 2/11/02 12:27 PM, Austin Franklin wrote:
> > Also, it would appear to me there may possibly be a depth of focus issue
> > with this sensor...
> >
> > I would understand a sensor array that has three sensors per pixel...with
> > a triple filter over each of the three sensors (the three sensors on the
> > same plane), but I don't understand the stacked sensors...  What IS good
> > about their discussion though, is they separate out sensors vs pixels ;-)
>
> I'm way out of my depth here (what else is new), but as each color is of a
> different wavelength, don't you stand more of a chance of getting them all
> in registration if the sensors are stacked to be at the right distance from
> the wave?
>
> God, I can't even phrase the question intelligently. I'm thinking of light
> passing through a prism. As each color comes out it gets "projected" to a
> different location. If you were trying to record each of those colors most
> sharply, wouldn't you want each color specific sensor to be in line with
> it's color as it comes through the prism? Does a similar thing happen to
> light as it comes through a lens?
>
> Todd
>
>
>
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