180 degree rule, ND filters and 24p

24 fps with a 1/48th shutter = 180 degree shutter. It relates to a film shutter, which being a mirror is best measured in degrees. Much better way of doing it than fractions. Lots about this online.
 
There is a black interval between video frames too. True 24 fps flickers horribly on electronic displays. The normal refresh rate for TV displays these days is at least 120Hz: 5x per 24 fps progressive frame, 4x for 30fps, not including any "smooth motion" interpolation BS. This eliminates the need for 3:2 pulldown conversion at 60Hz NTSC rates.
 
Liam Hall said:
...which being a rotating disc, is best measured in degrees.
Click to expand...

You are correct, that'll teach me for posting after a long drive :)

I would say they are spinning disc mirrors, but not all are - some are just there to blank the sensor.

I believe the Viper had a spinning mirror in it, despite having no optical look-through
 
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