So if we make our interpretation a bit more conservative, DXO is claiming the D800 somehow magically gains around some 7500-8000 discrete tonal levels (or luminance levels) by the simple act of DOWNSAMPLING (as they claim, anyway)? Fishy. And even if that WAS somehow possible, whatever you "gain" is artificial...the camera itself is still the limiting factor when you press the shutter button and capture a scene, in which case the D800, according to DXO's "screen DR" results, captures somewhere around 13.8 stops of DR.
If I understand correctly, DxO claims an increase in DR by the simple act of downsampling an image? This would seem to favor big MP cameras, and I question the legitimacy of the subsequent results.
As far as I understand, thats what their "print DR" tests are. I have been digging around DXO's site trying to find more explicit details about what "print DR" actually means, and whether they do any additional processing or not. Their site seems really slow and sketchy these days, so I keep giving up the search. Either way, it just seems extremely fishy to me that you can GAIN DR by downsampling. I'm fully aware that downsampling a high MP image to a normalized image size is a legitimate way to compare IQ between different cameras, however that is normally because of the normalization of noise and resolution...I've never seen it used anywhere else to claim a legitimate increase in DR beyond what the sensor itself is physically capable of. If DXO had claimed 14.0 stops rather than 14.4 stops of DR for the D800, I would have assumed that downsampling simply helped you realize the full potential of the sensor. Now, I am extremely skeptical of their "Print DR" ratings...
From a standardized testing procedure, I fully understand that they downsample to level the playing field between sensors of different resolutions. On the other hand, I can't possibly see how this scenario applies to actual shooting technique in real life. Obviously, if you buy a 36 megapixel camera, part of the appeal is the massive resolution. I can't see why you'd pay money for all those pixels, just to downsample an image and throw them away. However, this is precisely the scenario that DxO is simulating, is it not?
Yup, couldn't agree more.