6

This photograph was taken in my room which shows a foreground image of a teabag label and a background image of my laptop. As you can see the teabag label in front is in a sharp focus and the laptop at the back is blurred. And this is what we called 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. We can also define depth-of-field as the zone of sharpest focus in front of, behind, and around the subject on which when lens is focused on a specific subject.
Photograph above is a typical example of a photo with shallow depth-of-field control. (Only the main subject of interest is enhanced by throwing other elements out of focus)