My question is how to avoid banding in images made under LED lights using a full electronic shutter.
I am using a Sony AIII and Sony A9 cameras. When I photograph with the A7III using silent shutter (full electronic shutter) under LED lights, I often get soft-edged bands of lighter and darker exposure across the image. Why does this occur and how can I avoid it? I don't seem to get this problem (at least not to a degree that I have noticed it) with the A9.
I understand that if I use mechanical shutter at a speed under 1/60 second (1/50 in 50hz countries), I will avoid the problem because the shutter will be open for a full cycle of the LED light emittance. Why does the problem occur with full electronic shutter? And why does the A9 avoid it? I understand that the A9 sensor can do a full electronic scan and readout more quickly than the A7III or many other cameras. But I would think that would make the LED banding problem worse rather than better. But the A9 is much better about not banding when using full electronic shutter under LED lights.
How does all of this happen?