James Cameron (left) speaks about digital filmmaking as George Lucas (center) and Jeffrey Katzenberg look on during a panel discussion at the CinemaCon conference last week in Las Vegas. Mr. Cameron had delayed filming "Avatar" until digital technology caught up with his concept for the movie. (Associated Press)

James Cameron (left) speaks about digital filmmaking as George Lucas (center) and Jeffrey Katzenberg look on during a panel discussion at the CinemaCon conference last week in Las Vegas. Mr. Cameron had delayed filming "Avatar" until digital technology caught up with his concept for the movie. (Associated Press)