On Mar 30, 2010, at 17:14 , paul stenquist wrote:
I'm no expert on White Balance technology, but looking at Joseph
McAllister's dog pictures and David Parsons reporting shifts when
using
flash, could it be that, when using AWB, the amount of white or
very light
subject matter is making the changes happen? In the three pictures
of the
dogs, the nearer lighter coat dog is turning more and more towards
the light
source, and my guess would be that this is causing the AWB
algorithm to try
to correct for the change: unnecessarily in this case.
Couple of things:
One - when I went out to shoot the day after these images, I checked
the WB setting on my K-7, and I had it set on Cloudy, the norm here in
the PNW. So that explains to me why the photos were so sunny. The
camera was trying to compensate for the blue grey cast that wasn't
there. My bad, but not likely to be the cause for the color shift in
the one frame. The images I posted were uncorrected as shot. To put
them into my gallery, I corrected them.
http://gallery.me.com/jomac in the segment 2010.03.
Two - I have had this happen in auto WB with both the K20 and the K-7
in the middle of a string of images, not just at the end of a set. And
as far as the dog being the largest "close to white" object in the
photos, I don't think the Auto (or set by menu choice) WB looks at
that, or attaches very much weight to it if it does. Because it does
not know what color that dog is. I think the algorithms it uses looks
for color casts overall and tries to eliminate them, based on common
scenes that in this case contain dirt, a little dirty concrete, grass,
and dogs. On which Aperture 3.0 will do face recognition of all the
regular dogs at the park as well as the people, once I identify them.
Hope I don't have to spend too much time correcting Aperture's
guesses! But it will save keyword and caption entries in the EXIF.
It's a good thing that technology is coming to the fore, as some times
on some days, I get thrown the heavy mental blocks that come with age
and are so frustrating. Last night, it was the official flower of
India at Tuesday Night Trivia. I could draw it. I could see it in so
many designs. But the best I could do (under pressure, you understand)
was Trillium. Knew it was wrong. Tri is not 5, and Penta had nothing
to do with the name of the Lotus. But never did get there until the
answers were revealed. In my defense, no one else in our team of 12
with ages ranging from 21 to 67 knew it or challenged my Trillium
answer. No matter, our team won, as we frequently do, on the strength
of our identifying pictures of singers from the past, and our in depth
knowledge of the TV series Firefly (and Serenity, the movie). My $2
buy-in netted me $10 for a profit of $8, as I drank only their free
coffee. Very light night, as we usually walk out $20-$30 richer per.
You do understand how ADD affects one's though processes after all
that, do you not?
Joseph McAllister
Lots of gear, not much time
http://gallery.me.com/jomac
http://web.me.com/jomac/show.me/Blog/Blog.html
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