A mildly technical article by the film’s cinematographer revealing how certain scenes were filmed.
As per Fun Facts about Film | All the President's Men, the newsroom set “utilizes false perspective in the rear set area to increase the depth and scale-size for camera.” I believe I read somewhere else that the actors in the “distant” background of that set are in fact little people, not full-sized actors (a common movie production design practice).
I always liked the scene of Woodward and Bernstein in the Library of Congress going through stacks of, I think phone records. The camera switches to an overhead view and then moves up in a sequence so eventually, we see the entire reading room with them barely noticeable.
AtPM is very high on my list of all time favorites. I also watch it periodically. Despite the fact that I have seen it many times, I still get caught up in how the investigation unfolds.
