In this Film and Theater video tutorial you will learn about depth of field and how to adjust it. Depth of field means how many objects are in focus in the frame at one focus setting. If the depth of field is large, more objects at various distances from the camera are in focus. The first factor is the amount of light. If the light is good, more objects will remain in focus. On the other hand if you zoomed in with a long focal length lens the depth of field will reduce and lesser objects will be in focus. And if you zoomed out, more objects will come into focus. The video explains these and other aspects of adjusting depth of field by using an example of an athlete running over a series of hurdles.