Mirror, Mirror on the Wall
All About Eve is the gold standard of classic cinema. Shot entirely in black and white, interior scenes were filmed first in San Francisco and on the Fox soundstages in Los Angeles. Some location shots were done in New York City prior to beginning major shooting. A sixty-piece orchestra rehearsed the score, then played it again as the film was screened so the conductor could get just the interpretation he wanted (source). Mankiewicz uses his camera to show a variety of viewpoints, and bounces images off an assortment of mirrors as he tells his tale.
Close-ups are used frequently to show our glamorous leading ladies and men, but also to emphasize the difference in age between Margo (Bette Davis) and Eve (Anne Baxter). Davis is often shot without wigs or with creams on her face, or tired and drunk, while the youthful Eve and her youthful hands are almost always shown perfectly coiffed and radiant. The film both criticizes age discrimination and perpetuates it, by using the exact same techniques it condemns.
The film also employs one of the earliest uses of the freeze-frame, just as Eve reaches for her award… the action is frozen before she can grab it. That's the cinematic equivalent of Kanye interrupting Taylor's acceptance speech. We'll-ah let you finish Eve, but we want to say that Margo Channing is the best. (Source)
Just as Eve studies Margo, the camera also studies Margo from a variety of other characters' perspectives, whether it's the obsessive Eve or the loving Bill. The film also employs lots of mirrors—characters looking at themselves in mirrors, characters looking at others in mirrors. It's impossible to tell sometimes if you're looking at the actor or the actor's reflection. It's a brilliant way of illustrating how Eve is a reflection of Margo… but maybe the parts of Margo she wishes weren't reflected.