Watch Air Current (1975) Official Trailer

A movie film shot continuously is a series of action shots, one frame at a time. This is because there is a continuation of movement between the images in one frame and the next. On the other hand, since each frame is a single photograph, it is possible to trim and enlarge or reduce the image frame by frame. For example, if the normal zoom process is A→B→C→D, by enlarging and reducing each frame, it can become C→A→D→B. This is not unnatural since a movie is a series of photographs. The movement of the subject is continuous within the image that is enlarged and reduced frame by frame.