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 in a focused subject in an image can be quite subjective.here are two photos that you can definitely see depth of field in.
this photo is taken by annie leibovitz this shows alot of depth of field,only 3 things are focal because the 3 things are right front of the picture but you can still see the buildings and the trees in the background.