Deathwalker wrote:
> "Skip M" <shadowcatcher_at_cox.net> wrote in message
> news:p4q6c.37432$Zp.16991_at_fed1read07...
>
>>And I quote:
>>"The Sigma SD9 is the first digital camera to use Foveon's revolutionary
>
> new
>
>>X3 image sensor that features three layers of embedded photo detectors.
>>They take advantage of the fact that red, green and blue light penetrate
>>silicon to different depths and this allows full-color to be measured at
>>every pixel. These layers are positioned to absorb different colors of
>>light at different depths, so one layer records red, another layer records
>>green and the other layer records blue. This means that for every pixel
>
> on
>
>>a Foveon X3 image sensor there's actually a stack of three photo
>
> detectors,
>
>>forming the first and only full color system."
>>Notice "for every pixel on a Foveon X3 image sensor."
>>From Steve's Digicams
>>http://www.steves-digicams.com/2002_reviews/sd9.html
>
>
> "On the other side of the coin a conventional sensor only acquires 1 third
> of the colour. Cos it uses only 1 sensor per pixel and has to interpolate.
> some cameras deliberately blur in order to hide the artifacts." not an
> exact quote due to steves copyright protection.
Quote exactly under "fair use". The references to his site are more
valuable to him.
>
> The sensor has only 1/3rd the resolution of the foveon method. Remember what
> i said about Intel? Well this is the same as traditional microprocessors
> running at 3ghz and a sigma running at 1ghz but acheiving the same number of
> megaflops (millions of floating point operations per second). amd use a
> performance score rather than use their true megahertz. The claim of
> 10.2million pixels is really equivalent resolution of 10.2 million but close
> enough.
Spatial resolution in x,y is not improved with color resolution in z.
Canon's spatial resolution in x,y suffers slightly from interpolation.
The basic resolution of the Foveon is about 55 lp/mm from 3.43 Mpix.
The basic resolution of the Canon 10D is about 68 lp/m from 6.3 Mpix.
However, the Canon 10D, as stated only sees one color at that "rate",
and interpolates. Various figures put that interpolated resolution at
some other number, lower than the Foveon... (sorry, I have no idea how
to calculate it, here's your chance to be the man TP).
In resolution charts posted on dpreview, the 10D appears to resolve
slightly better than the Foveon, however.
Looking at some photos that George put up a couple months ago, there
were strange artifacts, jaggies and so on. Skin tones look decidedly odd.
jaggies: boat mast wires...
http://img2.dpreview.com/gallery/sigmasd9_samples/originals/img00172.jpg
http://img2.dpreview.com/gallery/sigmasd9_samples/originals/img00183.jpg
clock face filigree.
http://img2.dpreview.com/gallery/sigmasd9_samples/originals/img01371.jpg
Canon: no jaggies...
http://img2.dpreview.com/gallery/canoneos10d_samples1/originals/030325-1118-41a.jpg
Cheers,
Alan
--
e-meil: there's no such thing as a FreeLunch.
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