I find it interesting that in that article, the author uses in-camera JPEGs for the ISO comparison (e.g. at ISO 6400) & additionally doesn't downsize the 36MP D800 image to 22MP (which is a fairer comparison). It's pretty obvious that the Canon JPEG has more aggressive NR applied -- the text on the books are not as sharp on the Canon as on the Nikon. I believe a RAW analysis is more telling. Furthermore, DXO scores are normalized, which when combined with the sensorgen.info's extrapolated quantum efficiency for the D800 vs. 5DIII (56% vs. 49%), might explain the higher ISO score DXO gave to the D800.
IMHO, though, I don't see much of a difference in ISO 25,600 performance between the two cameras after the D800 is resized (bicubic) to 22MP (both 5DIII & D800 images were converted using ACR, with identical settings, and please note these images are from Imaging Resource and are not mine
(Canon 5DIII on top
| Nikon D800 on bottom
View it at 100% here: http://f.cl.ly/items/2k0k1Z402w1s3j3y1W2G/5DIII_vs_D800-ISO25600-2.png
Maybe a slight advantage to the Canon. So, yes, DXO's 'Sports' score does make me scratch my head a little (the two cameras should at least be equivalent). Perhaps their normalization equation needs to be modified. In video mode, for sure, the 5DIII absolutely trumps the D800, most likely b/c the latter line-skips which, in combination with its smaller pixels = bad high ISO. But that's in video. With images you can effectively bin pixels to get a cleaner image at 22MP. And for those of you who find resizing invalid for comparison -- do you really need to deliver 36MP images to clients?
Furthermore, I also find it interesting that in his examples of shadow lifting, where he concludes that both cameras perform equally, his posted shots are something like 25% & have so much JPEG compression that I can't come to any conclusions at all. Fred Miranda's comparison, on the other hand, showed 100% crops that used high enough quality JPEG compression as to not show compression artifacts.
So while his comparison may be totally valid by some standards, I would caution you to make your own conclusions/comparisons if this 5DIII vs. D800 issue is a big one to you. I personally was also pretty skeptical of DXO... that is until I started performing my own Stouffer Transmission wedge tests & derived similar DR numbers. More importantly, these numbers matched my real world control scenarios between Canon & Nikon sensors. But the whole reason that scientific testing methodologies are developed to begin with is to try & remove variables for objective comparison. This is what DXO does. Again, I do believe the author is correct to raise an eyebrow at the ISO scores given to the 5DIII vs. D800, but I'm willing to bet this is some fault of their normalization equation. Also, it does irk me that DXO doesn't fully publish their full testing protocol, as most scientific journals would require you to, so I'm not saying they're a holy grail or anything. For example their 70-200 f/2.8L II analysis was entirely unreasonable, most likely due to a bad copy (which they themselves admitted). But to conclude that the shadow recovery at ISO 100 between the D800 & 5DIII is pretty much a wash... well... after all the evidence to the contrary...
Also, it should be pointed out that it's a fallacy to think that extra highlight headroom means there's some magical extra DR you can recover from Canon vs. Nikon files. Highlight headroom is a direct result of how the manufacturer's map the data from the sensor to the file and, yes, I have found that a D7000 blows channels 2/3 a stop earlier than a 5DII & 1/3 of a stop earlier than a 5DIII, but the overall extra DR of the D7000 comes from the recoverable shadow detail, which is significantly cleaner than Canon's. Same goes to comparisons of the D800 vs. MF sensors -- the D800 requires a different shooting philosophy whereby you purposefully underexpose the image, and then pull detail out of the shadows. Back to Canon vs. Nikon: if the 5DIII has an extra 1/3 stop of headroom, you'll want
to push the actual exposure by 1/3 of a stop (compared to the D7000), but even then your shadows won't be as clean as the D7000 exposed 1/3 stop less. My point is: to do a valid DR comparison, you need to find the overall
number of steps any given sensor is able to resolve on the wedge, where SNR>1 (or whatever arbitrary value of your choosing).
Finally: the author complains about the D800 Live View implementation hampering his ability to focus properly & that that may have led to Canon winning the Seattle skyline shot from Kerry Park. Why didn't he use contrast detect focus in Live View? When I do comparisons, I actually specifically use contrast detect focus in LV b/c it's arguably the most accurate way to focus as long as your subject has some contrast (albeit on Nikon you'll have to remember to do that with the aperture wide open for greatest accuracy)...
But even then, I disagree with his statement that Canon won in that Kerry Park shot comparison... I downloaded his full-size JPEGs, and if you look at 100%, it's pretty clear that the Canon shot has had significant sharpening applied to it whereas the Nikon JPEG has not (you can tell b/c the Canon shot has sharpening halos all over it; none on the Nikon shot).
So then I downsized the D800 shot to 22MP, & then applied 176 Unsharp Mask in PS (Radius 1), and 108 Unsharp Mask (Radius 1) to the 5DIII... to get them looking about equivalent sharpness to my eye in the buildings... the Canon needed less sharpening b/c it'd already been sharpened, & even after all this, the Canon file suffers from more sharpening artifacts
, yet resolves less than the D800
... and that should be no surprise
. It, frankly, surprises me that anyone could come to the opposite conclusion
. I also tweaked brightness/contrast to get the two images to look similar, for easier comparison.
See for yourself: 100% views, D800 on left
| 5DIII on right
View it at 100% here, paying special attention to the detail in the areas circled in red: http://cl.ly/GVCI/D800_vs_5DIII-KerryPark_RonComparison.png
A bit long-winded, but I find his conclusions questionable, to say the least, in light of all these factors. One must be extremely careful to not walk into a comparison with any inherent bias (hard to do), lest results be skewed in favor of the original hypothesis. It doesn't seem like the author had this intent/bias, so honestly I'm a bit surprised at his entire article.
I shoot with a Canon 5D Mark III, and have been with the 5D line all the way back to the EOS-3 (haha), by the way. But boy have I wondered about switching, lately...