Depth of field is the distance between the nearest and farthest objects in the scene that you want to take a picture of. Depth of field refers to the amount of your picture that will be in focus and how much light goes into your camera. A camera can only focus it's lens at a single point if you want it to but you can change it to where it focus' on everything. This is not a fixed distance, it changes in size. A large depth of field means that most of your picture will be in focus including both, the objects close to your camera and the one farther away from your camera, this makes the image a deep depth of field because it includes a lot to all of the image. Whereas, a small depth of field means that only a certain part of the photo will be in focus the rest of the photo will appear blurry or fuzzy which is also called a shallow depth of field.
Iman Khan