Something that's always interested me is how cameras implement LV exposure simulation. Initially we might assume the camera simply configures the sensor to the shooting parameters (shutter speed, ISO) to yield the brightness/exposure simulation in Live View. But that has downsides - for fast shutter speed / high ISO situations the LV preview will have lots of noise, and for slow shutter speeds the preview will be stuttered. In fact some cameras implement it this way, such as Panasonic, and it doesn't work well.
Here is a glimpse on how Nikon does it on their Z cameras, using the Z8 as an example. I first took photos of my 500Hz Arduino LED, to establish what the bands look like at various shutter speeds. Note that at very fast shutter speeds (ex: 1/8000) the bands are very distinct with a near 50% duty cycle of light/dark, since each row captures exactly 1/2 of a light cycle, either ON or OFF. As the shutter speed is decreased the black portion of each band gets smaller - this is the result of sensor rows capturing both the light and dark parts of each LED cycle, as a function of the exposures not being aligned with the LED cycle.
Then I connected the Z8 to my HDMI recorder and captured what 1/8000 looks like at various ISOs. You'll see that the camera alters the actual sensor shutter speed to simulate the ISO in LV. You can determine what specific shutter speed the camera selected for each simulated ISO by matching the LV screen grab in the botton half to the shutter speed photos in the top half. Note that this isn't a static relationship - the camera will change the set of shutter speeds it uses to simulate ISO based on the Light Value of the scene, to keep everything centered / reasonable.
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