While exploring shutter angles, I found out about the rotary shutter. I understand that these were developed primarily for movie cameras, but the first thing that came into my mind was: surely this mechanism would have created an uneven exposure?
Mathematically, as the radius of the circle increases, the diameter increases too, so that the part of the shutter further from the axis of the circle would be exposed for a longer time?
In this crude example I've drawn, when turning clockwise, the black shutter exposes a top corner first:
but as it continues turning, the lower part is exposed fully for what appears to be a longer time:
...while the upper corners are not exposed:
So wouldn't the upper part of the sensor be less exposed? And if so, how was this compensated for?