The 70D...has not improved and is slightly worse than the 9 year old 20D.
Oh, I think it's a little better. I hope your analysis really was quick, because I'd hate to think you wasted even more time. Per-pixel SNR? Funny, I haven't seen that phrase on the display placards at Best Buy or my local camera shop. I wonder why? I know...because notwithstanding a minuscule number of DR-obsessed Canon-bashing forum jockeys, no one who buys cameras cares. The 70D is a massive improvement over the 20D in 99.9999% of ways that matter to people. Canon will sell loads of 70D bodies, quite likely more than the D7100 by a wide margin.
DxOMark measures sensors, but people buy cameras, not bare silicon sensors. You can rehash DxOMark data until hell freezes over, it doesn't change the fact that Canon has been outselling Nikon for years, nor the fact that the 5DIII outsells the D800. The obvious conclusion is that 'better' sensors (where 'better' is defined as low ISO DR) have not helped Nikon or Sony sell more cameras.
So. . you're waving a flag and cheering because the sales/SNR charts for the last 10 years look good?..
perhaps if Canon's sensors improved as much as their oft' touted sales figures these recurring discussions wouldn't exist.
FACTS STILL STAND: At a per-pixel level, NO SIGNIFICANT IMPROVEMENT IN 10 YEARS.
I think the time I spent putting together the animated graphs and essay demonstrates that perfectly.
Don't forget, I didn't just compare the 70D in a previous graph with the d7100, I deliberately chose the sub-$600 consumer-class D5200.
But yes, I'd prefer a 70D to a 20D for the wealth of other improvements and the fact that, at least at base ISO, the performance is comparable with higher resolution and the few higher ISO levels I use are also still adequate.
but that doesn't change the facts about the sensor system tech | NO SIGNIFICANT IMPROVEMENT IN 10 YEARS FOR STILL IMAGES
But maybe Canon is finally approaching a corner of sorts and, when they finally change their course, they'll be able to provide customers with actual sensor performance improvements along with all the other bells, whistles and flashing lights they're so good at adding to the mix.
I wouldn't go that far, on a PER IMAGE basis, the 70D does quite a bit better than the 20D at ISO3200 due to a full stop better SNR and 2/3rds of a stop better DR and TON less banding which makes high iso shots that have lots of darker portions much more likely to look acceptable. And at low ISO you are talking 20MP vs 8MP so you get a lot more detail for say landscape shots and a lot more reach for say birds.
High ISO improvements have been crawling along but nobody has really crawled them along any faster they are all stuck in a very tricky zone where it is not easy to make big strides at this point with current technology.
Canon has been often falling behind in color sensitivity though and has fallen way behind in DR. In fact they were actually getting worse in terms of DR and banding for most of the last half decade and only recently have just managed to get almost back to where they had gotten to with the old 1Ds3. Even Nikons own non-Exmor sensors that don't even use column ADC managed to improve well over a stop in DR over the time while Canon's got like 1/2 stop worse. Canon went from reasonably well controlled banding in the 1Ds3 and 40D at low ISO to gobs of it with the 50D and 5D2 and it is not until the 1DX and 6D that they even started beginning to head back to old 1Ds3 and 40D levels, the 70D may finally be fully back there again or perhaps even better, not sure yet.