OK, now your objection is clearer.

First of all, the issue I addressed has nothing to do with how much of the recorded range has more read noise than shot noise (and read noise is significant far above this range, especially if there is 1-dimensional or "banding" noise, which is much more visually potent than 2-D noise). The issue is *what* the level of read noise is in ADUs, as this will be the minimum noise found anywhere in the image, in a linear sense, relative to the steps of the digitized levels. If quantization doesn't happen where there is only read noise, it shouldn't happen at any other range, where shot noise increases the absolute noise level.

The premise is that with a read noise of 2.0 ADU at ISO 100 in the 5D (not the same as the 1Dmk2), the number of levels used can be divided by 2.0/1.4, or 1.43, without incurring any practical quantization in the RAW data. The other way to look at it is that the steps can become 1.43x their current size. In this case, that would mean that the number of levels between black and RAW saturation in the 5D at ISO 100 could just as well have been recorded with about 1000 less levels (about 2500 instead of about 3500). It is not about clipping levels away from the shadows (or highlights, or anywhere).

Just curious: http://blog.lexa.ru/2008/01/16/balans_belo...inim_gisto.html

This guy performs the Hue/Sat analyse with PS. Russian document.

Sorry to recall this post, but a forum member of POTN forum has depicted (http://photography-on-the.net/forum/showthread.php?t=485349) a much easier way to obtain a UniWB on any camera than my whole procedure: the point is that what we are seeking for is an image which is already balanced (R=G=B ), so that when the camera tries to calculate the WB multipliers over it, they will be the closes possible to 1.0 1.0 1.0.

And which is the easiest to produce already balanced image? any shot where all three channels are saturated on every pixel, i.e. pure white, and that's as simple as shooting your camera to the sky or any bright area with the lens wide open for some seconds. Once we use the resulting image for in-camera WB calculation, the multipliers will be the closest to UniWB.

I have done this in my camera and achieved multipliers:

multipliers 1.006856 1.000000 1.005877 1.000000

I cannont improve that, surely because some hot pixel or whatever. A a max error of 0.69% for the R channel is simply outstanding.

Regards.