Continuing his outspoken advocacy for the use of film stock over digital formats, Cinematographer Wally Pfister not only chose to shoot the film in the anamorphic format on 35mm film instead of on a digital camera, but also finished the film photochemically, refusing to use a digital intermediate.
When Evelyn checks into the hotel that Will reserved for her after transcending, she tells the check-in attendant that she has a reservation under the name "Turing". Alan Turing (1912-1954) was a British mathematician and computer scientist who was the inventor of the Turing Test, a process where a person communicates with a live person and a computer, without seeing, and has to figure out which one is the live person. He also developed the "Turing machine", a theoretical computing model that is the conceptual basis of digital processing. He is widely considered to be one of the fathers of computing in general, and artificial intelligence in particular.
Rebecca Hall, Paul Bettany, and Kate Mara have all appeared in the Marvel Cinematic Universe. In Iron Man 2 (2010), Kate Mara had a small role as the U.S. Marshal, and Paul Bettany provided the voice for J.A.R.V.I.S.. In Iron Man 3 (2013), Rebecca Hall had the role of Maya Hansen, and Paul Bettany provided the voice for J.A.R.V.I.S. again.
The copper-wire mesh that Will constructs around his yard at the beginning of the film, and Max's team later uses to capture Martin, is a Faraday Cage, a concept which is normally employed on a smaller scale to protect sensitive electronics from RF interference.