I created a demonstration for the support of my statements re the D3X and 5D2 evaluations.
a. I used the raw files from Imaging Resources, because they are suitable (more or less), and I don't have any others suitable. They were recorded in 12bit mode (why on earth); this would pose a problem *if* the DR of the D3X were really so large; however, it is not.
b. These shots are not exposed as low as I would prefer them to be. Therefor I used only the red channel, which is more than 1 EV darker than the green and about 0.8 EV darker than the blue on grey patches (under the current illumination).
c. I selected only such patches, which are enough clean and evenly illuminated; not like this: http://www.panopeeper.com/Noise/D3Xvs5D2/C...yTestSheet.GIF
d. It is not necessary to have any high exposure when measuring the DR; only the dark end is interesting.
e. The 5D2 has a small disadvantage in the measured ISO (less than 1/3 EV); this affects the noise characteristics, but not the dynamic range. The test images have compensated for that difference by the shutter time.
f. I highlighted with red one or two numbers over the image. The last number in the upper raw per color group (identified as DR) represents the average pixel intensity on the selection, measured from saturation downwards. The last number of the color group in the second row (identified as NP) is the noise in the salection, measured as standard deviation, expressed as percentage of the average intensity. 100 times the reciprocate of this number is the SNR. NOTE: this number has nothing to do with "stop".
Example: in http://www.panopeeper.com/Noise/D3Xvs5D2/C...ISO00100_b.GIF
the intensity is -8.62 EV, the noise is 19.48%, which corresponds roughly to SNR=5.
g. The D3X raw pixel values are not linear (nor are the 5D2's, but they are compensated for), therefor the very dark patches appear to be darker than they really are; I have not highlighted them.
Finally, the measurements:
a. Medium dark patch: the intensities are virtually identical: -6.92 EV vs -6.97 EV. The D3X patch is cleaner; noise: 6.59% vs. 7.56% (very low, visually not perceivable).http://www.panopeeper.com/Noise/D3Xvs5D2/N...ISO00100_a.GIFhttp://www.panopeeper.com/Noise/D3Xvs5D2/C...ISO00100_a.GIF
b. Dark patch: the advantage of the D3X is now visually perceivable; the noise is only 15.4%, vs. 19.48% of the 5D2, at the intensity -8.62 EV.http://www.panopeeper.com/Noise/D3Xvs5D2/N...ISO00100_b.GIFhttp://www.panopeeper.com/Noise/D3Xvs5D2/C...ISO00100_b.GIF
The question is, how much difference in EV does this difference in noise represent. To find it out, I searched for a patch in the same 5D2 image with closely comparable noise. I found one with noise 15.55% (very close to the 15.4%), at the intensity -8.29 EV. This means, that the 5D2 requires 8.62-8.29=0.33 EV more light to have the same level of noise as the D3X. Measurements on different spots show like or slightly larger difference, and it can be somewhat greater in even darker spots.http://www.panopeeper.com/Noise/D3Xvs5D2/C...ISO00100_c.GIF
Here it would be interesting to see darker patches. Unfortunately, the community of this forum is more interested in flaming than in providing usable raw files.
The difference is gone on the medium dark patch (actually, the D3X sghows slightly higher noise, but negligable).http://www.panopeeper.com/Noise/D3Xvs5D2/N...ISO00200_a.GIFhttp://www.panopeeper.com/Noise/D3Xvs5D2/C...ISO00200_a.GIF
The darker patch shows a slight advantage of the D3X:http://www.panopeeper.com/Noise/D3Xvs5D2/N...ISO00200_b.GIFhttp://www.panopeeper.com/Noise/D3Xvs5D2/C...ISO00200_b.GIF
The 5D2 has clearly lower noise than the D3X, on the darker patch as well:http://www.panopeeper.com/Noise/D3Xvs5D2/N...ISO00400_a.GIFhttp://www.panopeeper.com/Noise/D3Xvs5D2/C...ISO00400_a.GIF;http://www.panopeeper.com/Noise/D3Xvs5D2/N...ISO00400_b.GIFhttp://www.panopeeper.com/Noise/D3Xvs5D2/C...ISO00400_b.GIF
The gap is widening to the advantage of the 5D2:http://www.panopeeper.com/Noise/D3Xvs5D2/N...ISO00800_a.GIFhttp://www.panopeeper.com/Noise/D3Xvs5D2/C...ISO00800_a.GIFhttp://www.panopeeper.com/Noise/D3Xvs5D2/N...ISO00800_b.GIFhttp://www.panopeeper.com/Noise/D3Xvs5D2/C...ISO00800_b.GIF
The D3X is clearly not a high ISO camera. http://www.panopeeper.com/Noise/D3Xvs5D2/N...ISO01600_a.GIFhttp://www.panopeeper.com/Noise/D3Xvs5D2/C...ISO01600_a.GIFhttp://www.panopeeper.com/Noise/D3Xvs5D2/N...ISO01600_b.GIFhttp://www.panopeeper.com/Noise/D3Xvs5D2/C...ISO01600_b.GIF
UPDATE: semicolons removed from the image URLs