Final answer:
With a 180 degree shutter, the time exposure is 1/2 of the duration of each frame per second, typically resulting in a shutter speed of 1/48th of a second for 24 fps. For other frame rates, divide the fps by two to get the correlating shutter speed. Faster shutter speeds are needed to freeze action.
Step-by-step explanation:
With a 180 degree shutter, it's 1/2 the time exposure, which is the equivalent of your exposure being open for 1/2 of the time for each second of video capture. In terms of exposure per second, if we are dealing with a frame rate of 24 frames per second (fps), a 180 degree shutter would typically equate to a shutter speed of 1/48th of a second, since each frame would be exposed for half the time it takes to move to the next frame (1/24 sec is the duration for one frame, therefore 1/48 sec is half that duration).
However, if the camera operates at a different frame rate, you would adjust accordingly. For example, at 30 fps, a 180 degree shutter results in a shutter speed of 1/60th of a second. The basic rule is to divide the frame rate by two to achieve the equivalent shutter speed under a 180 degree shutter setting. Faster shutter speeds like 1/250th of a second or more are generally required to freeze action, depending on the speed of the subject.