Depth Of Field

According to http://www.mir.com.my/rb/photography/fototech/htmls/depth.html depth of field  is the amount of distance between the nearest and furthest objects that appear in acceptably sharp focus in a photograph.

This photo by Annie Leibovitz has a very big depth of field as the closest object to the viewer is the person and the furthest is the horizon of the sea.  

All of the shot is in focus as none of it is made blury to bring focus to another object. 

Most of this photo is in the shades of blue and cream and the person is wearing a dress which is a very dark shade of yellow which draws attention also she had bright red hair and is obviously made the main focus of the photo.

on this site it tells you what short depth of field and long depth of field can be used for and how to change/ control things to achieve either short or long depth of field.

http://www.tutorial9.net/tutorials/photography-tutorials/depth-of-field-in-photography/