If you saw "black bars" on the sides, they didn't set the theatre right for displaying the proper "Academy flat" ratio of 1.85:1.
"Les Miz" was filmed that way, for some unknown reason for an "epic" of this scale. The two most common aspect ratios for modern films are 1.85:1 and 2.35:1, also known as CinemaScope.
Both are widescreen formats, but CinemaScope is the widest. Most action movies today or big adventure movies are shot in the wider format. It makes the movies feel more expansive and just plain "bigger."
Many smaller dramas and comedies still use the Academy ratio. Up until recently Spielberg also preferred this ratio. Of his earlier films, Jaws and Close Encounters used CinemaScope, but E.T., The Color Purple, Schindler's List, etc., all used the Academy flat ratio. And Woody Allen always shoots in this format. There are other "epic" movies, such as Out of Africa, that were shot Academy flat, not the wider CinemaScope.
There is an opinion by many directors that this ratio is better for actors and "acting." Audiences will focus more on the acting and less on the expansive scenery. I disagree with this. A good director and cinematographer can frame scenes and capture performances very well in the wider CinemaScope ratio.
Although, I will say that a majority of the Oscar-winning performances since the 1970s have come from Academy ratio films, not CinemaScope, so there may be something psychologically to that format.
"Jaws is the Citizen Kane of movies."
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