NEW YORK -- Through cinema history, audacious, lengthy tracking shots have captivated filmmakers and movie buffs who marvel at their grace and choreography. In the middle of Joe Wright's critically acclaimed ''Atonement,'' a 5½-minute shot unfolds as Robbie, a British World War II soldier (James McAvoy), comes upon France's Dunkirk beach, where the final point in the British retreat from the Germans is portrayed as a grim circus of defeat and chaos. In the Ian McEwan novel from which the movie was adapted, the scene is described in just a few pages. McEwan writes: ''It was a rout and this...