You should leave it a 16x9 for widescreen movies (unless it is non-anamorphic), native if you are pixel-mapping, and 4x3 or SDTV. If you can't stand the bars, perhaps a CH setup might be better for you.
My best answer for your question is that, artistically speaking, I think directors choose different ARs depending on the type of film they are directing, and I guess some feel that certain ARs work better in certain scenarios. And of course, some directors may have used a different AR than others for the same movie. I think huge battle scenes do better in a 2.35:1 than 16:9 so you can get that huge, immersive feeling in the middle of battle. But then again, Spielberg chose 16x9 for Saving Private Ryan (and Band of Brothers), but it works for that movie.
All in all, I like the fact that they can choose the format - because I know that they know better than me what works best for their movie.
Anyone else agree?
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