On Sun, 18 Nov 2001 02:03:55 GMT, "Kirk_" wrote:

>I am in the market for a higher end consumer mini-DV. I see that the
>highest priced ones all have separate CCD's for each color and that is
>supposed to be better. I have to wonder though, the 3 CCD units all say
>they either have 270,000 or 380,000 pixels each, while some of the higher
>end single CCD units have well over a million pixels.
>
>Why are three separate smaller [pixel-count] CCD's any better than one
>very large [pixel-count] CCD?

Hmmmm....
I cannot tell you technically why, but I can describe the
visual results of the four basic types you will likely
encounter with various brands/models of camcorders:
- one-chip, normal pixel count (about 340,000 pixels):
average resolution (low resolution if DIS/EIS used)
and so-so color, plus the usual shortcoming of one-chip
images of problems rendering good tone in highlight and
shadow areas (but the lower pixel count translates into
better sensitivity for low-light performance, all else
being equal - though the Sony "HAD" chip compensates
for this, and some for color quality...).
- one chip, high pixel count (about 680,000 pixels and
higher), same image qualities as above if the area used
for imaging is the same after DIS/EIS used, but often
with better color and on-screen resolution if a larger
number of pixels can be interpolated down to form the
image (and the higher pixel count translates into
lower sensitivity for low-light performance, all else
being equal - though the Sony "HAD" chip compensates
for this, and appears also to improve color quality...).
- 3-chip low pixel count (270,000 X 3) results in "pixel
shifting" being needed to gain back the resolution lost
(in some colors only - but this appears also to have
some other negative effects that show on contrasty
parallel edges), but otherwise the color, tonality, and
picture smoothness can be good (and the lower pixel
count translates into better sensitivity for low-light
performance, all else being equal - though the Sony
"HAD" chip can compensate for this...).
- 3-chip normal pixel count (340,000 X 3) results in good
image sharpness in most colors, the best "smoothness" in
the image, excellent tonality (good rendering of image
parts in dark through very light subject areas, making the
image look less harsh, with "open" shadow areas and
highlights that have color instead of "burning out" to
white), but with, all else being equal, less sensitivity
(though the Sony "HAD" chip compensates for this,
improving sensitivity, and also color...).
Often "oversharpening" and increased contrast are used
to compensate for lower inherent resolution to make
the image look sharp, but these have consequences: the
oversharpening produces "halo" edges of white or black
on contrasty edges, oversharpening and increased contrast
exaggerate various image compression defects and also
low-light "gain-grain", and increased contrast reduces
the range of tones that can be imaged, produces a "harsh"
look, and makes accurate exposure more difficult.
BTW, you can find reviews of various Mini-DV camcorders,
with frame-grabs, motion-video descriptions, and
sound-quality descriptions, at:
www.David-Ruether-Photography.com/camcorder-comparison.htm