have been following this thread for a while. It would seem that the big question in your mind is whether the dynamic range of the 5D3 is greater than the 5D2. The DxO tests put them in the same range. The D800 higher yet. The testing method is to downsize the images to a standard size for comparison. The similar resolutions of the two 5D bodies and the similar results show that Canon made no real progress in that department at lower ISO settings. At higher ISO, the 5D3 does pull ahead. The Nikon, with 50% more pixels, gains a little bit of noise reducing averaging as there are more pixels to mash together to create each pixel in the downsized image. This is how the rating of around 14EV can happen for a 12 bit file which at each individual pixel can only have a maximum of 12 EV. Both the Canon and the Nikon use 12 bit systems. In the real world we don't get all of it to use in our photos due to noise floor levels, the analogue amplification which adds noise, and the conversion process to digital which isn't perfect either. From the comparisons between the 5D3 and the D800 it would appear that Nikon emerges as the winner for less noise at the pixel level in the digital files that we wind up with. In low light (high ISO) DxO did show the 5D3 having greater dynamic range than the D800 but the 5D3 plateaued at settings under around 800 while the Nikon continued to improve as the ISO setting was reduced.

After looking over a lot of charts, graphs, and comparison photos I'll still continue to do as I have always done with digital cameras. Take a test shot, look at the histogram to see how the camera did, and walk away smiling with a proper exposure the first time, the second time with a compensated exposure, or if the dynamic range exceeds my sensors abilities a set of bracketed exposures. When I post process it is not very often that I adjust exposure and when I do, it is seldom by more than a third of a stop. I rarely have visible noise in my shadows from the 5D bodies. I will point out that if I push the exposure it does get ugly, especially in LightRoom, but not to the same extent as in Fred Miranda's posted shots. Yes, I did some major pushing in every piece of software I have just to see what happens. I do suspect that upsizing didn't improve the situation, but it is an area of ugliness that Nikon seems to have managed to not create in the first place. It is quite safe to say that the D800 does deliver better shadow details when pushing exposure.