I think the Beluga point picture does a good job of illustrating the
strengths and weaknesses of the CCD sensor.
http://zone-10.com/d1/node/341
The sky in the distant horizon is aqua colored, but at the top of the
picture it's a deep blue. There is not just a brightness change, but a
hue change as well. CMOS sensors are less likely to capture the hue
change, but will usually be better at capturing the brightness change.
In this picture, there is actually little difference in brightness
between the horizon and the top of the frame, but that's mostly a
result of editing.
The source images were all taken with the 14-54 set to 14mm in the
vertical orientation.
The weakness of the CCD technology is also apparent in the clouds in
the right half of the image. Highlight recovery is a color accuracy
mess. With CMOS, I can crank the highlight recovery slider all the way
to the left with little color shift in the highlights. But with CCD,
the clip point is so different between the RGB sensels that it will be
a mystery what color you're going to end up with, but one guarantee is
that it won't be neutral.
While this problem is rather pronounced on the Olympus CCD cameras, it
is NOT exclusive to Olympus. I've seen the same characteristic on
image files from other Kodak sensor cameras, as well as the Medium
Format backs from different manufacturers.
I believe this is by design. From what I've managed to decipher, the
CCD sensors (especially those by Kodak) are adjusted to require
minimal adjustment for the mid-tones. The clipping points are
different, but if you don't highlight recover too much, you'll never
see the artifacts. The CMOS sensors (particularily those by Canon) are
adjusted so the clip point is the same across all three colors
sensels, and sensitivity curves are adjusted for each channel. So the
mid-tones are not naturally there as in the CCD images, but are
corrected.
This sample image is per my own level of visual insanity. The knobs
are turned ALL the way up.
AG Schnozz
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