Now that we know they've officially started filming, one thing I'm slightly confused about is the scale of this thing in terms of action/CGI. I can totally picture the dramatic thriller version, but it's mostly just people in interior locations - rooms and labs and hallways - stressed and arguing and being covert. What I can't quite picture, though, is the version of this movie that needs *more* production/post-production time than Nolan's effects-heavy action epics like The Dark Knight, The Dark Knight Rises, Inception, and Tenet, all of which (originally) had July release dates as well, but didn't start filming until spring of the previous year (roughly May-ish). Throwing in Interstellar and Dunkirk as well, no Nolan film has started filming *this* far out from its release date, and it's not even close, really.
So, I'm wondering what this movie is, exactly, if there are all kinds of massive war scenes as well or what? Because the only other explanation I can think of is that with names this big, and a cast this size, it's more of a scheduling issue, and Nolan simply needed to start this early to accommodate the actors' busy schedules/other projects.