I dont think you're seeing the big picture. DXO resizes all to 8mp because that's probably the smallest MP they have in their DB, so it makes sense.
however, if I'm shooting a 5Ds compared to a 6D, of course the 6D will be better at the pixel level at ANY ISO, however resized to equal levels is the only way to do a fair comparison. If both the 5Ds and 6D shot at 6400 and resized the 5Ds to match the 6D, we better hope that the 5Ds can match the 6D. If it can, then it's a clear winner, since it can also do 50mp. In practice that means that the 5Ds can print ANY size good as or better than the 6D.
the DXO test is just comparatively speaking, not pixel level, and it really does say a lot about noise performance. At the pixel level, pretty sure, the 5Dc beats the 5D2, however when normalized at 12mp, the 5D2 is the clear winner.
The downside with the 5Ds is native 6400...... considering that the 7D2 has native 16000, what's canon's excuse for native 6400?
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