> Cropping the sensor is a common way to counter rolling shutter with current camera
Not in my experience. For full-frame 35mm digital cameras, the most common way to counter electronic rolling shutter effects is, ironically, a very fast mechanical shutter.
In digital cameras with mechanical shutters, which include all Canon/Nikon/Sony/etc. consumer DSLRs and mirrorless cameras, the electronic shutter programmed to stay open for much longer than the mechanical shutter, which allows there to be a time instant when all pixels are simultaneously electronically open. The mechnical shutter then opens and closes during that time.
The rolling shutter on a Sony a7 is about 26ms. Mechanical shutters can beat that easily, and can be as fast as <0.2ms.
(Electronic shutters can be faster on a per-line basis. But they will still take 26ms to roll through the image for a rolling shutter sensor. So if your electronic shutter is set to 0.01ms you'll still be seeing 0.01ms exposures at each line but it will take 26ms to roll through the image.)
I don't think you're right about mechanical shutters being faster. The type of mechanical shutter on most cameras like this is a focal plane shutter[0]. It has two curtains - an upper one and a lower one. When the shutter is closed, the two overlap. For a long exposure (typically anything longer than 1/100s although some cameras are faster) the lower curtain will fall all the way, then the upper curtain will fall to close it off again. But at faster shutter speeds, the upper curtain will start falling before the lower curtain has reached the bottom, and so you can get exactly the same rolling shutter effect with a mechanical shutter as with an electronic shutter. For very fast shutter speeds, the exposure is a narrow slit between the two curtains that travels down the image at a much slower speed than the exposure time, and this is why most cameras can't synchronise with a flash at speeds faster than 1/100s or so. So therefore the type of mechanical shutter in most DSLRs and mirrorless cameras effectively have a rolling shutter transition time of 4-10ms, which is much more than the 0.2ms you claim.
Video-specific cameras are where this might be improved, because you can have a shutter which is a rotating disc, and this can allow faster opening/closing times, because it doesn't need to speed up from a standstill for each frame.
There exist central shutters which are mechanical shutters that act as a global shutter, but these are unusual because they need to be built into each lens you attach to the camera. These are typically limited to a maximum speed of 1/500s.
Not in my experience. For full-frame 35mm digital cameras, the most common way to counter electronic rolling shutter effects is, ironically, a very fast mechanical shutter.
In digital cameras with mechanical shutters, which include all Canon/Nikon/Sony/etc. consumer DSLRs and mirrorless cameras, the electronic shutter programmed to stay open for much longer than the mechanical shutter, which allows there to be a time instant when all pixels are simultaneously electronically open. The mechnical shutter then opens and closes during that time.
The rolling shutter on a Sony a7 is about 26ms. Mechanical shutters can beat that easily, and can be as fast as <0.2ms.
(Electronic shutters can be faster on a per-line basis. But they will still take 26ms to roll through the image for a rolling shutter sensor. So if your electronic shutter is set to 0.01ms you'll still be seeing 0.01ms exposures at each line but it will take 26ms to roll through the image.)