To make video motion look smooth and natural, like in a movie, what special rule links your video's frame rate to its shutter speed?

The special rule that links your video's frame rate to its shutter speed for smooth, natural motion, like in a movie, is known as the 180-degree shutter rule. This rule dictates that your shutter speed should be set to approximately double your chosen frame rate. Frame rate, often expressed in frames per second (fps), is the number of individual still images recorded or displayed sequentially per second, creating the illusion of movement. For cinematic aesthetics, 24 frames per second is a widely adopted standard. Shutter speed is the duration for which the camera's sensor is exposed to light for each individual frame, typically expressed as a fraction of a second, such as 1/50 or 1/100. Adhering to the 180-degree shutter rule means that if your frame rate is 24fps, your shutter speed should ideally be 1/48th of a second, or practically 1/50th of a second due to common camera setting increments. The primary purpose of this rule is to achieve the appropriate amount of motion blur, which is the natural streaking or blurring of moving objects within a single frame caused by their movement during the sensor's exposure time. This specific level of motion blur, created by exposing each frame for half the duration it is displayed, mimics how human eyes perceive movement and how traditional film cameras historically operated with a physical 180-degree rotating shutter that blocked light for half of each film frame's exposure cycle. This consistent and natural motion blur is essential because it smoothly connects one still frame to the next, preventing video from looking unnaturally sharp, choppy, or exhibiting a "staccato" effect that is often described as feeling too digital or hyper-realistic, thus making the motion appear smooth and natural to the viewer.