I might be wrong, but from what I've read, when the movie is filmed, it's shot in "16:9", which is wide screen format. 16:9 is generic though. When it's actually filmed, it might be 16:8 or 16:7 which will make the bars at the top and bottom, 16 being the left to right, and 7, 8, or 9 being the top to bottom. I had the same question because renting new DVD's, and grabbing the copy that says widescreen right on it, still have the black bars, and I was wondering the same thing. I guess as widescreen is becoming more popular, more movies and tv programming will be filmed in 16:9. Hope this helps.