I believe Shel uses PSCS, which shows the histogram before, during, and
after conversion modifications. The BMW shot wasn't underexposed
overall. In fact the wheels were close to maximum highlight. But this
crop comes from the shadowed rear panel.
Paul
On Sep 25, 2005, at 9:43 AM, Cory Papenfuss wrote:
There seems to be a fair amount of noise in the pix generated by my
DS.
Here are two examples - each 100% crops - taken directly from
unmanipulated
PEF files. I've noticed this since the very first pix I took.
http://home.earthlink.net/~scbelinkoff/bmw_noise.jpg
http://home.earthlink.net/~scbelinkoff/pic_noise.jpg
The first was shot @ 200 ISO, where the DS is supposed to be virtually
noiseless, the second @ 400 ISO.
What could be causing this noise? Underexposure? Some camera
setting that
needs changing or adjustment? I can clean it up a bit with ACR, but
should
that be necessary?
I would speculate that it's underexposed. I would say to look at the
histogram, but both the in-camera and most RAW converters' histogram
are done after the gamma-correction, brightness, and contrast settings
have already been applied. I use 'ufraw' for one of my RAW converters
and it will show the before and after histogram.
My experience has been that the -DS tends to underexpose by about
to 1 stop in typical compositions if left to its own decision. That's
good to prevent blown highlights, but bad for shadow and mid-tone
noise. If your RAW converter and workflow allow, try making a RAW
conversion to 16-bit linear TIFF (without *any* adjustments or color
profiles applied). Look at the histogram on the resulting deep color
image to find out what exposure the sensor *REALLY* saw.
-Cory
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* Cory Papenfuss
*
* Electrical Engineering candidate Ph.D. graduate student
*
* Virginia Polytechnic Institute and State University
*
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