Final answer:
A moving shot where focus changes is called a Focus Pull Shot. This technique necessitates changing the lens's distance from the film sensor to maintain focus on different subjects at varying distances.
Step-by-step explanation:
The moving shot where focus changes, bringing objects into and out of focus, is known as a Focus Pull Shot. This technique adjusts the focus of the camera during the shot to direct the audience's attention from one subject to another or to highlight the spatial relationship between subjects. A focus puller or a camera assistant often performs this task. The camera lens cannot be fixed at a constant distance from the film for focusing on both near and distant objects because of the principles of optics. When focusing a camera, you adjust the lens's distance from the film sensor to change the focal length as required to keep your subject sharp. This is because objects at different distances project light differently onto the film plane, and to create a sharp image, the lens must be adjusted to account for these differences.