1. A display apparatus comprising: a display to display an image; a first tracking unit to generate position information on a user positioned relative to the displayed image; and a second tracking unit to capture a first image of the user, to determine a portion of the captured first image corresponding to a position of the user, based on the position information, to zoom in the portion of the captured first image, and to track a gaze of the user upon the displayed image by analyzing the zoomed in portion of the first image.