Description:
This is Prospect Park West in Brooklyn (a street in limbo somewhere between Flatbush and Park Slope). The bank was located just to the left of the white buildings on the corner (of the side of the street facing you in this photo). The exterior bank shots and almost all of the film itself was shot on this street (the interior bank shots were a set).
In 1975 the location was a real bank, but is now some other kind of business. It's obvious that the back of the building shots were not the true back of the building. I have been on this very street on a hot summer day, and it's so cramped and grimy and ordinary, that you would never in a million years guess that a film like Dog Day Afternoon had been shot there.