There is little difference in IQ for any DSLR at ISO 100. You are buying features and hype.
For landscapes, more MP will give you more detail, but as MP count goes up, so does the difficulty in actually getting that extra bit of resolution. There are some who do very well with high MP cameras, but the average photographer is not obsessed with a incremental increase in resolution, the more important elements such as composition and subject, lighting, DR, etc put and IQ improvements far down the list. In fact, I don't even know how to measure something hypothetical like IQ that only exists in the mind of a photographer and is different for each of them. We can measure several parameters, and they trade off against each other, but IQ? That sounds like something DXO would assign a number to
There is a pretty huge difference at ISO100. That is actually where cameras differ the most since they are all pretty solid at high ISO now. But at low ISO some have one to THREE AND A HALF stops better dynamic range than others. For many scenes that doesn't matter at all, but for many potential scenes it could.
70D RAW file appears to show the same old DR as Canon has been stuck with since 2007 . I hope it is not their new process sensor!
My guess is Canon's noise problems are not really with their sensor, but with the downstream high frequency electronics. In other words, DIGIC. It seems most other manufacturers have moved to on-die processing of some kind...Sony with CP-ADC, and others with something similar...on-die ADC. Canon supposedly had similar technology with the 120mp APS-H (the press releases explicitly called out on-die "parallel image processing", which I can only figure is ADC)...why they haven't put the technology into practice is beyond me.
Yeah it depends upon your definition of sensor. If you are talking solely the photon capture and not a whit else than yes their sensors are very good, even the current ones, I believe, capture more than 14 stops DR, I forget the numbers but it might even be closer to 16. But the electronic readouts/ADC and such that are in some cases on and more or less a part of the sensor too and in some cases just off sensor are much worse and yeah that is where the problem lies. Exmor makes it all part of the sensor in a much different way.
From what I've found around the net, Canon's on-die circuitry is quite good. Their analog CDS is some of the best, which is probably what gives them the edge in terms of high ISO noise performance.
The ADC is slightly parallel (8-channel per DIGIC 5+ these days), but housed off-die in the ADC. They are also responsible for processing a considerably greater number of pixels each than the column-parallel on-die ADC that Exmor has. I think its the high frequency, bucket-parallel nature of Canon's off-die ADC that introduces the most offensive banding noise (the vertical stuff). I think there is some lighter banding, both horiz and vert, added by the non-uniform response of analog CDS transistors (which is apparently the reason why Sony moved to digital CDS).
If Canon could follow Exmor's lead....move the ADC onto the sensor die, go column parallel...even if they did not go fully digital like Exmor, that should improve things. Each ADC would have to work less hard as it would have to process fewer pixels. They wouldn't need to be clocked as high, so wouldn't introduce as much noise. Another trick Exmor employs is moving the PLL off into an isolated corner of the sensor die, away from the ADCs themselves, along with all other high frequency components...which apparently helps reduce noise introduced during ADC as well.
I'll grant ankorwatt ONE thing here: A smaller fabrication process, 180nm or smaller, would certainly help Canon achieve success in migrating more logic onto the sensor die.
Anyway, as I was saying though, the Canon bean counters maybe hear all the talk about video being the next big thing and figure putting the money into whiz bang stuff like dual-phase AF (especially since their mirrorless stuff was getting killed in reviews for AF and that market is apparently big in Japan) makes more sense since when they look into forums and see everyone who tries to complain about DR get driven away and the ones who stay getting mocked as DRip DRippers and figure they don't need to bother, nobody cares about DxO scores or trying to capture more types of scenes (as more DR allows) and maybe so long as people defend them to the ends of the Earth in the forums and beat down the Drippers and Ankorwatt and such and people don't get scared away and they keep decent sales they maybe figure safer to be conservative and not lose out jobs than push forward and spend more to improve DR no matter how small the risk just in case ROI takes some time. It's also harder to get fired for sales not improving a lot and not totally dominating compared to Nikon (as I suspect would have happened had they pushed top AF into 5D2 and top sensors into 5D3/60D) and easier to look bad for a big one quarter expenditure to push stuff like that forward? Who knows.
I don't personally have a problem discussing DR, even begging Canon for more. I've argued, here on CR, both sides of what I guess is a rather fine line...not long ago I got stuck in a DR debate and had to produce my own photos with 14 stops of DR to demonstrate how Canon lags behind the rest of the industry. I don't deny they need to work on it. I would love to discuss it more.
I do have a serious problem with ankorwatt, however. He is unfathomably narrow sighted, makes ridiculously inaccurate claims on a regular basis, has an unbeatable bias against Canon, and seems to do everything he can at every opportunity to bash and beat down Canon as an incompetent, incapable competitor that produces products unworthy of even being spoken about, rumormongored about by Canon fans, etc. He interjects debate into every single thread, makes bold claims that are completely false, obfuscates at every opportunity, directly insults and berates other members (particularly about their intelligence), and is otherwise the largest pain in the rear end I can imagine. I greatly dislike him, and for some reason, despite considerable effort to leave the issues be...I just can't seem to let some of his comments go. I think everyone, including myself, is sick and tired of hearing about how much ankorwatt thinks the D800 and Sony Exmor are the greatest thing since the Breath of Life
itself woke man up out of the dust of the Earth, and yet none of us can get away from it. He's always there, either starting a new argument or berating some member, always over the same thing even when the topic has absolutely nothing to do with DR, sensors, or the D800. I think he is the root cause of 90% of the debates on this forum, the ever-present antagonist, and I think we could have far more civil discussions about dynamic range, sensor technology, etc. if he wasn't around pushing every Canon-fanboy button he can find all day every day. I try to exit debates with him as quickly as I can if I end up in one, and I try to ignore as much else that he says as possible. One thing I just can't let be, however, is anyone believing him when he says that Canon is incapable of competing in the marketplace, is incapable of building a new fab and therefor must use other manufacturers technologies, or that the only way to produce good photos is to get a D800. If someone wastes their money believing that crap, dumps their kit, and buys into Nikon only to find out they despise the ergonomics, or the menus, or any number of other Nikon features that are inferior to Canon's...well, I'd always feel I could have spoken up and given them a more realistic basis upon which to base such a decision.
I do think Canon needs to improve their fabrication technology and get up to date with modern sensor design. I don't think anyone here really thinks otherwise. I think everyone who needs it would LOVE to have the kind of DR other cameras have. I think people react to the antagonism they feel from ankorwatt specifically, and maybe a few other non-Canon members generally, so the reaction is to defend their chosen brand, rather than have a more civil discussion about the rumors and technology that interest them. It isn't really the DRivel...sometimes its just drivel...and people get sick of it. It would be awesome to have a normal discussion about DR and sensor technology without having to fight about it over idiotic points that don't really matter in the end. It would be awesome to read a Big MP or 7D II rumor thread without wondering on which page the pointless debate is going to begin, and whether I'm going to read something I just plain and simply can't resist responding to because its so asininely idiotic...and yet believable enough that some poor sap is going to read it, think the wrong thing, and end up wasting their hard earned money jumping brands without first having all the facts. Bah.
Anyway...I agree. Canon needs to enter the modern age. They need to improve their sensor technology. They need to improve their dynamic range. They need to respond to their customers requests and deliver. I think they can, too...they certainly did with the last round of camera releases (the big outcry before the 1D X was "fewer megapixels, higher ISO w/ less noise")...unless they really truly have become bean-counter central and despite their capability, are really only interested in the bottom line. (If that IS the case...well, at some point the competition's better sensor technology will eventually hurt
their bottom line, forcing them to react in kind.)