I have it on good authority that a 5DSR Mark II is due late 2018. Here are some things I have learned and some other items that are extrapolated from this to complete the picture: Note some of this comes from rumours, some from information I personally heard about a working prototype (which may be different to production models.)
Camera Name: EOS 5DSR Mark II.
Low-pass filter: No low pass filter fitted, no ‘cancellation device’, simply a sensor without the filter. There will NOT be a 5DS Mark II. Dire warnings of moire problems have proven to be pretty much unfounded in general shooting.
Resolution: 9546×6364 (60.75 megapixels)
Maximum framerate: 5.6 fps in 60 mpx mode, faster in crop mode and faster still in new full-frame 1:2 resolution mode (4473×3182 pixels, 15.2 megapixels) – I hear at “EOS 1D class speeds”. Unknown if the 1:2 mode uses pixel binning or not.
Note: this is somewhat disappointing as it would mean that the camera doesn’t have on-chip ADC as the 5.6 rate for 60mpx is equivalent to the maximum throughput from the 24mpx sensor in the most recent APS-C cameras. But then I guess any faster and it’d kill sales for the Mark IV dead.
[UPDATE: Thinking more, if it outputs cropped data direct from the sensor then it pretty much guarantees ADC on the sensor. Otherwise there would be very little difference, if any, in performance between the different modes. In which case, the ADC doesn’t seem to be offering much benefit at full resolution]
Video: 4K video using 1:2 mode with approx 10% horizontal crop. But don’t expect codecs to be any better than the 5D IV. This is not designed as a 4K video camera.
DIGIC: system unknown, probably twin DIGIC 7.
Other Features: Touchscreen system as from 5D Mark IV. Wifi, NFC and general software features as per 5D Mark IV.
Body: casing identical to 5D Mark IV, can use the BG-E20 battery grip.
And… FINALLY focus peaking for manual focus in live view mode (just perfect for those new tilt-shift lenses!) – this may come as a firmware upgrade for 5DIV owners too and possibly for other current cameras but don’t hold your breath.
Price: Don’t expect much change from $5000, it will be significantly more expensive than the Mark IV. Or, maybe with some luck, it’ll coincide with a price drop on the Mark IV and come in at a more reasonable price.
My source did suggest that Canon may hold off on the 5DSR Mark II until they can get a reliable sensor with on-chip ADC which should dramatically improve the framerate at 60mpx. If that is the case we’d expect to see a 24mpx APS-C sensor with on-chip ADC as the next product – and that would mean the 7D Mark III. And super framerates in a 7D Mark III would mean something would really have to be done to improve mirror speed, so it’s likely we’d either see a pellicle mirror 7D Mark III, some kind of OVF/EVF hybrid allowing better live view shooting or, less likely, full mirrorless. We’d then see it in the 1DX Mark III before eventually, some years down the road, seeing it in the 5D Mark V.
Personally, I think they will not worry about on-chip ADC for the 5DSR II as that would kill 5D IV sales dead.