Michael Chapman, director of photography, Taxi Driver
One storytelling device adapted from literature is the idea of perspective. While camera angles, focal length and lens speed all serve the needs of film grammar, point of view is also an important element. There are two primary points of view:
FIRST PERSON POINT OF VIEW – Audience sees events through the eyes of the character
THIRD PERSON POINT OF VIEW – Camera presents story as seen by an ideal observer
Once in a while, directors are able to assume both subject positions within the same shot. In Martin Scorsese's Taxi Driver the camera was deployed to emphasize the isolation and paranoia of the main character, Travis Bickle. In this short example we see the camera used in both the 3rd person and 1st person perspectives within the same shot.
Director of photography, Michael Chapman later discussed the shot:
"The shot where Robert DeNiro goes this way and the camera goes that way and shows all his world that he experiences and then comes back and finds him. The crew was sort of shocked by that...the idea of letting him go that way and the camera go that way almost offended their sensibilities. After a while they got used to that because they realized it was Marty but none of them had worked with Marty before...It was all about making it a documentary of the mind."
Oddly enough I noticed a similar technique used in the TV western series, Wagon Train. In the episode, "The Clara Beauchamp Story", director Earl Bellamy moves seamlessly from 1st person to 3rd person within the same shot.
Who knows where Scorsese got the idea? Maybe watching late night Wagon Train re-runs, or maybe Godard cribbed it and it founds its way back to Scorsese via the French New Wave.