Dark rooms with shadows are used heavily in this film. The director shows Benjamin's room as dark and shadowy to parallel his personality. This is also seen in the Robinson house. Shadows everywhere with light on only part of the characters' faces tells you that this is a house of mystery and uncertainty. The director places lights seemingly on the ground to cast huge shadows of the characters on the walls. This makes you feel that the director's idea is to have the characters' deepest secrets and personalities "overshadow" the characters themselves.
The pool scene where Benjamin Braddock is in the SCUBA suit demonstrates another film technique. The director uses a shot from inside the suit looking out towards the family. You can't hear anything. It let's you know how Benjamin feels about his current life. He is just going through the motions of life. Then, when Benjamin is under water sitting perfectly still, the director goes from a close-up and fades out until you can't see him anymore. This makes you think that the character is sick of it all and that he is about to change.
Over-the-shoulder shots, odd angles, and shadows are all used in the hotel scenes. Benjamin doesn't want anyone to see him there. The director conveys this message with a shot that puts the large podium between the clerk and Benjamin; an "over-the-podium" shot.
After the first affair with...