They have global shutter sensors around the 12 megapixel level. They could split the sensor up into different processing paths. Do these 200 megapixel phone camera sensors have really bad rolling sensor issues? They are using electronic rolling shutters like your R5 when in silent mode or whatever canon calls it now.

What 200 mp phone camera sensors? The iPhone 14 is closer to a 12MP digital camera (quad bayer 48 million sensors). And from what I recall, 8 or maybe 10 bit. So in comparison to the 211MB of sensor data coming off the R5, there's 36 to 45MB of data coming off the phone camera. And I believe the 14's max shutter speed is 1/1000, so there's up to 35 times less data needing to be read off the sensor (45GB/s versus 1.6TB/s)

And I'm sure there is multiple processing paths - I just don't know the fine details about how that raw data is slurped off the sensor.

The Z9 has an electronic shutter, and fast one at that. So prepare to see that tech to hit lower tier mirrorless cameras in the next years.

Not sure what I'd need frame rates above 100 for stills so, but that's just me, because it sure is cool.

My 2016 olympus pen-f, which wasn't exactly ground-breaking technology when it came out, already had an electronic shutter that worked with the full resolution of the sensor.

It's a 20 MP micro 4/3 sensor - so 1/4 the surface area of "full-frame".

Just realized, the Nikon 1 we got for Christmas for my daughter seems to have one as well... Need to test that! Still, we look at a 10 MP sensor smaller in size than a DX. Heck, the more I look at the Nikon 1 series, the more I realize to ehat extend it served as a mirrorless test bed for Nikon.

Do you expect the physical size of the sensor to have a bigger influence on this than the resolution?

Depends on the sensor, doesn't it? The more dynamic range, the more data a sensor is collecting.