Let’s get some of these specs out the door:
15 Stops Dynamic Range
61 MP (9504 x 6336) - Full Frame - Exmor R CMOS Sensor
240 MP Pixel-Shift Multi Shot
$3500 available July 18, 2019
5.5-stop 5-axis in-body Image Stabilization
BIONZ X Image Processor & Front-End LSI
567-Point Phase-Detection Autofocus
10 FPS still shooting
Dual UHS-II SD card slots
For the record: Hasselblad claims 14 stops of dynamic range from the Medium Format X1D II 50C, so for Sony to state 15 stops from a smaller Full Frame sensor is quite the remark. Or in other words; more pixels shoe horned into a smaller area.
Hasselblad: 50 MP in 44 x 33 mm
Sony: 61 MP in 36 x 24 mm
Not to be overlooked during Sony’s press release: The ECM-B1M digital microphone. Digital microphone? Yes! Meaning instead of an analogue signal processed by the on-board analog preamp (microphone-in), the signal goes straight to the camera CPU for recording to the SD card. One less step in the processing chain + no need to worry about microphone cable manufacturing quality. $350 available July 18 from B&H.
Video
4K UHD 3840x2160p 23.976 / 29.97
100 Mb/s H.264 Slog2/3 and HLG
4K from 20 MP 6K Oversampling crop of Full Frame sensor (same area/resolution as shooting with a6500 APS-C camera)
Read between the lines: The greatest video attraction of the a6500 ($1100) is that it uses the entire APS-C sensor to shoot 4K from Oversampled 20 MP 6K. Now you get that exact same footage while shooting video with the A7R IV since it takes precisely that crop from the middle of the 61 MP sensor. Yes the A7R IV is 3x the price but now you have one camera in the bag that executes both maximum resolution stills and excellent Super 35mm 4K video.
Unfortunately HDMI out is still 8-bit 4:2:2, but oh well life goes on. This is especially unfortunate since HLG is supported in camera yet said format is all but standardized as 10-bit H.265.