Extra DR is pnly usefull if the image is taken with it. For the average image with only 8-10 DR then the possible extra from the D800 is just not used.
Good pp ensures the printing issues are resolved before printing.
I agree, somewhat...
Having a camera with extra DR means you'll have cleaner shadows, even if your image didn't contain anything as dark as the extremes the camera can record at some given SNR. Thing is, many common scenes DO contain a wide DR.
Real world example below.
I just did a recent portrait shoot using 5D2 at ISO 100, outdoors (ughh) but at least on a cloudy day. Using a 580EX2 for flash fill yet!
Using the RAW tab in DPP:
Processing in DPP displays a raw luminance histogram ranging from -6.5 to +3 EV un-adjusted, pretty decent considering that it shows a full range for the 5D2 of -9 to +3.8-ish. This looked fine when chimping the shot on the back of the 5D2 and using the RGB histogram.
But back at the shop
* Things are a little dull so +.67 EV added in DPP.
* People are wearing dark gray and black dress pants with some sheen, + 2 clicks of shadow adjust so you can see some detail in the dark, but not darkest areas.
* -2 clicks of hilite adjust to soften the sky reflections off a receding hairline
* -2 clicks on contrast to slightly soften the whole scene so no blocked shadows or hilites or unpleasant contrasts.
Image is now beautifully balanced tonally, it will print well. Except for.. what's that I can see?... plaid pattern noise on the darker areas of the (almost) black pants! And they've been lit a little extra from the shadows using fill flash!
In an 8x10 size print, we won't notice it, the pattern noise blends into the dark areas. If I print about 12x18" tho, it'll be visible; to ME anyway.
These are common adjustments to present a nicely balanced, professional-looking image that's not too contrasty. I've seen far too many "pros" frequently provide grossly contrasty images to clueless customers. They can't complain about shadow noise they can't see because they've clipped it to black, along with some real shadow detail. These photogs may as well use a cheap point'n'shoot but that's a rant for another time.
Summarizing, many common scenarios, even using some fill light, can provide a wider DR than expected, 9.5EV in this case on a cloudy day using fill light. Properly toning an image can require lifting the shadow regions enough that the pattern noise can show up in dark areas that are large enough not to obscure them from our perception. Printing larger will also make the pattern noise more apparent.
If you really light your scenes well, expose the right a little, without clipping, and bring it back down in post, you won't see this issue. If you work in the real world with minimal lighting control, even a simple cloudy day portrait shoot can show up the weakness in Canon's shadow noise. If you're shooting landscapes on a sunny day and have a wider DR and you need to compress it to make the image look how you want, you will run into this problem as well.
So to those few I often spar with here on this issue, the above is a real world scenario that's not even an extreme example and it'll STILL show up the weakness of Canon's sensor tech some of us complain about.
Hence whey I ask if they shoot (in real world lighting), process, and print. Because if they do, and strive for a nice looking final image, then they will run into this. It's just a fact.