If this means "completely new" then the EOS R sensor is completely new. So were several of Canon's 18mp sensors.
It takes probably quite a bit more effort to halve the readout speed of a sensor than to go from 4,3fps with AF (5DIV) to 5 (R).
Is there any real confirmation of this? It would neatly explain the cropped 4k issue. But at first glance it flies in the face of 50mp x 5 and 20mp x 16, all at 14-bit. Not to mention the readout for DPAF to work as well as it does.
I always guessed that Canon's cropped 4k was a processing issue downstream, not a readout speed issue.
Speaking of sensor readout speeds...didn't the 42mp A7r II switch to 12-bit RAWs in continuous shooting mode?
The 5Ds / 5Dsr were released 5 months prior to the A7r II and could do 50mp x 5 fps x 14-bit. Am I correct in understanding that it took Sony "less than two years of development" to finally catch up to Canon on this spec? It sure looks that way from the A7r II manual.
In the case of the 5DS' 50mp x 5fps and the 1DXII's 20mp x 16fps, the only thing these cameras' sensors are tasked to do when performing these bursts is to simply pumps out exposures. The reason the A7RII dropped to 12bits is that, being a mirrorless, it's also performing AF / AE, and at 3fps, provides a liveview feed in burst. Now we're at 8fps in 14bits with AF and liveview feed in the case of the A7RIII with a 42mp camera.
BTW, all of Canon's M cameras drop to 12bits in burst as well, and none of them manages to provide a liveview feed in between frames in continuous drive mode. That's a key area of performance that is yet to be known with the R.
It's fairly easy to know that Canon's sensors struggle with readout speed : the M50's or the 5DIV's significant rolling shutter in cropped 4K is all we need to know. If Canon wanted to provide FF 4K, they'd need to skip so many lines that IQ would be hideous.
BSI was supposed to improve high ISO. It made no practical difference in FF sensors. Reading forum posts you would think Canon FF sensors must be behind on high ISO. Looking at actual RAW files they're right at the top.
Nikon and Sony's best DR sensors beat Canon's best DR sensor by 1 stop on DR. At base ISO. If you ignore dual pixel RAWs. That 1 stop amounts to a couple ticks on a noise slider when pushing shadows.
Nobody but Canon has DPAF. Which is a rather complicated sensor engineering feat. While I have video spec related complaints about the EOS R, early reviews indicate it's one of the best focusing MILCs out there. Meanwhile Nikon Z models are getting hammered for AF issues in early reviews. Do they not use Sony sensors? I guess you can't blame them. It's only the recently released gen 3 Sony A7 bodies which offer decent FF AF in the Sony mirrorless line.
For all the endless talk online about "superior" Sony sensors the 3 year old Canon 5Ds and 5Dsr still easily tie the D850 and A7r3 for image quality and large prints at low ISO, and are only very slightly behind at high ISO.
Let's address the rest. BSI was never supposed to improve high ISO for larger sensors. It's only for smaller ones that it does. However BSI does enable a more flexible approach to wiring the sensor, and that's on thing that helped enable the A7RII, A7RIII or D850's readout speed (as Imaging-Resource interviews suggest). More importantly it's also a prerequisite for stacked sensors. No BSI ? No stacking. So far we've seen no BSI from Canon. And a patent means zilch for consumers if it can't be produced at a specific cost.
DPAF undoubtedly is the future but it doesn't come for free or without compromises, particularly for stills cameras. One inconvenient of it is that DPAF sensors can't feed both phase information and actual image information at the same time to the camera (analysis of DP raw files suggest that DPAF sensors have only one ADC path and can't read the A and B channels at the same time). Given the M50's rolling shutter in 4K, I suspect that the reason there's no DPAF in 4K is that the sensor's readout speed is too slow to both perform a DPAF reading and an image reading. Masked pixels sensors are compromised in many ways, but they can provide both phase AF and image information at the same time. In 2018 DPAF isn't the bee's knees. It will increasingly be once readout speed increases.
DP raw is not a practical solution to increase DR in all cases as you can get parallax errors, and it doesn't play nice with the softwares most people use. That said as JonSnow suggested DP raw prefigures the sort of exciting things we'll be able to do with our cameras. Well actually, it's the iPhone that really prefigures that, but I digress.
And finally, the 5DS(R) isn't only slightly behind at high ISOs. It's a full stop behind (particularly under warmer TCs as its blue channel noise is elevated) :
That could be partly explained by another sensor trick that is yet to be seen in a Canon camera : current Sony sensors use Aptina's dual gain architecture to have, basically, two base ISO values (64/100 and one higher up, around 640/800) to improve noise performance.
And its DR deficit is a bit more than one stop. Compared to what is currently produced by Sony, it's rather 2 stops.
And before anyone thinks otherwise, let me just say that I'm a Canon user who's completely uninterested in Sony cameras, and who doesn't want to see a Sony sensor inside a Canon. But Canon's current deficit in terms of readout speed will have to be addressed at some point, as it's not just a question of IQ, but simple, basic operational qualities. As this article suggests, they may have quite a few difficulties ahead in that area.