Depth of field - Depth of field is the amount of distance between the nearest and farthest objects that appear in acceptably sharp focus in a photograph. A preferred selection Depth of field ("DOF") in a focused subject in an image can be quite subjective.
Aperture is important because it tells us how much light can pass through the lens. A lens that has an aperture of f/1.2 or f/1.4 as the maximum aperture is considered to be a fast lens, because it can pass through more light than, for example, a lens with a maximum aperture of f/4.0.
A shallow depth of field is where the background is blurred. To get a shallow depth of field the f stop needs to be low for example, f/4.
A wide depth of field is where we can see clearly deep into the image. To get a wide depth of field the f stop needs to be high, for example, f/22.
This image was taken on f/22 which makes the depth of field greater. We can see that the depth of field has been increased because both people are in focus. In this image I focused on both of them on purpose to create a high depth of field. The girl in the foreground could be focused slightly more.
This image was taken on f/4.8 which decreases the depth of field. As we can see the person in the background is completely out of focus and the person in the foreground is completely in focus.
