A lot of water under the bridge, so I have to summarise. I used to have a 5D mk3 and now own a 1Dc. Actually, measuring a chart in log is the ONLY way it makes sense. I agree that the result will never be conclusive since DR stops might show up in the chart that eventually proves to be unusable: color pollution in the highlights and excessive noise in the shadows. There is no common standard and "image overclockers" like Sony and RED have their issues. It's the price they pay by going for a marketable spec that looks good on paper. Some manufacturers lack the integrity and discretion, since their customer base don't ask for it. But even worse than this is a single individual that subjectively grades the files until they fit the agenda of the day. I know for a fact that the 1Dx/1Dc (and probably 6D as well) has a higher dynamic range than the 5D mk3—and I do mean in raw DR, comparing photos in Lightroom. The 1Dx/1Dc have technical specs that support the idea (larger photo sites, more advanced processing), but the proof is really in the pudding. The 5D mk3 still suffers from noise and banding in the shadows, something that has been plaguing Canon for many years. The 1Dx/1Dc and 6D sensors (possibly the 7D mk2) are different. I can lift shadows on my 1Dc in Lightroom by 4 stops without encountering the famous Canon banding. It is the distinguishing feature difference on the stills side. The 12 stops in Canon log (I think it's fair to say 12 if you are going to compare to other, significantly more optimistic numbers from other manufacturers) are what were left over after Canon discarded what they didn't feel lived up to their design standards. It isn't the highest number they could have come up with. The whole Canon Log image is usable without color artefacts. I agree that going after more than 12 stops in 8 bit seems like over reaching. 10 bits? Well, that's something else… I am very happy with the level of detail I get out of the 1Dc. It's of little point discussing this, since I think it's largely up to individual taste. I would say this: as long as the image processing doesn't add artificial detail by haloing, and the detail is strictly optical, I'll take as much as possible. I think this 1Dc 4k screen grab has enough detail for my taste (click to open):