Moosie wrote:
> I know that there is no way that a camera can get white balance
> right without some information or assumptions, which can take four
> forms.
Actually, I believe there is. The sensor is able to "see" absolute
colors. If, for example, it sees (exposure adjusted for calculation
purposes) "000,027,024" the camera's intelligence can be programmed
to immediately identify a certain subject or type of light. Based on
that, it can make an assumption. My Minolta A1 has the ability to
identify and know that the camera is being used outdoors in bright
sun. Based on that, it will adjust exposure and WB to compensate for
any meter-reading errors that might occur. However, throw a simple
polorizer or ND filter on the lens and the intelligence is
immediately thwarted and exposure and WB errors will occur.
Where I definitely have differences of opinion with you is in regards
to skintones and WB. You have been implying that they are inherently
linked. I disagree. I believe that skintones are a direct issue of
the initial response curves of the sensor and the bit-mapping that
occurs in the sensor's support chips or processor PRIOR to and
INDEPENDENT of the WB setting. I'm going to give you a case in
point:
This week I was photographing a conference where there was a table on
stage drapped in a purple curtain/cloth. Using IDENTICAL WB
settings, (adjusted with an ExpoDisc) and confirmed/verified in the
RAW converter, the Olympus E-1 (with Kodak sensor) captured the cloth
as purple. However, the Minolta A1 (with SONY sensor) would only
capture the cloth as blue. Not purple, but blue. Using RawShooter,
I have fiddled with the WB, Tint, Saturation and Hue to get the two
to match. It is impossible. For some reason, the Minolta's sensor
refused to capture this specific color correctly. I see these
differences all the time with LED stage lighting. This was such an
obvious difference that I am unable to mix-and-match images from the
two cameras. Exposures were also identical, BTW, regardless of
ambient or flash.
Same thing occurs with skintones. The Olympus skintones bias towards
pink regardless of the WB, Tint, Saturation or Hue settings. In
comparison, some other brands tend to bias towards "freezer-burned
shrimp".
AG
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