The shutter-open-for-half-a-frame or "180° shutter angle" is commonly recommended as a default for shooting video. It is the result of having to compromise betw

The shutter-open-for-half-a-frame or "180° shutter angle" is commonly recommended as a default for shooting video. It is the result of having to compromise between inaccurate recording and a blurry video when your frame rate is low. With 24fps and a small "shutter angle" you are capturing wrong information (e.g. resulting in wheels turning backwards) and you get a choppy look. With a large shutter angle you get too much motion blur. 180° is neither really correct nor really sharp, but it's the most commonly used compromise. These problems are really the result of a too slow frame rate though - with 60fps you can shoot with a 1/60 shutter, and you get 100% accurate playback while still having frames sharper than a 24fps movie (with 1/48 s shutter) and a smooth video. When you capture with a high frame rate (e.g. 120fps) and a 360° shutter angle (1/120s) you can also easily reduce the frame rate later without any ridiculous hacks like 3:2 pulldown by combining (averaging) frames or leaving them out, depending on the motion blur amount you want. Applying the "180-degree-rule" to frame rates other than 24 or 30 fps just comes from missing knowledge or misunderstandings from what I can tell.