What is Depth Of Field?

Depth of Field (DOF) is that amount of your shot that will be in focus. A large depth of field means that most of your image will be in focus whether it’s close to your camera or far away, whereas a small (or shallow) depth of field means that only part of the image will be in focus and the rest will be fuzzy

The size of the aperture has a direct impact on the depth of field. A large f-number such as f/32, (which means a smaller aperture) will bring all foreground and background objects in focus, while a small f-number such as f/1.4 will isolate the foreground from the background by making the foreground objects sharp and the background blurry.