On Sun, 2 Dec 2012 15:36:23 +0900, "David J. Littleboy"
wrote:


BobF wrote:

If you believe that, I have a bridge to sell you. AWB can't possibly work.
In principle. It can't tell the difference between a pink shirt in white
light and a white shirt in pink light. (More generally, it can't know what
the subject/scene was supposed to look like, so it can't infer what the
light source was. Are the walls off white or Wedgewood blue? Both will
confuse any AWB system.)

You're a bit behind the times... my new Nikon has a data base of thousands
of
photos which it uses to judge the exposure and colour... and it works quite
well, thank you. For example, it can detect a face and judge the colour's of
surrounding objects as well, looking for colour castes. Note that all humans
are
about the same tint, mostly differing by saturation and brightness values.
(Except for certain African's of course!)


Your friends don't include Asians and drunks.

Dunno about AWB, but I find the database-based AE a complete disaster. With
my old center-weighted cameras, I could look at the scene, realize it was
going to be wrong, and compensate. Database based may be good enough for
snapshots, but for landscape sorts of things, it really doesn't know what
you think is going to be important and gets things wrong randomly. Change
the composition slightly, and it sees a different pattern and changes the
exposure. Count me as not impressed.


I've often been surprised by the accuracy of the camera, even using those
awful
compact fluorescents.


Ah, reminds me. The place AWB (or any other WB, including manual after the
fact) really doesn't work is mixed lighting. But that's not the AWB's
faultg.

The tricks you play with your own unique sets of marks to indicate
quotation levels has rendered this thread almost incomrehensible.
--

Regards,

Eric Stevens