Shinjuku has a veritable city of cameras, just to the west of the (Shinjuku) station. Yodabashi Camera has SEVERAL buildings devoted to photography - one is just film and processing (I didn't use it, but you could), and an entire floor of another is Large & Medium format cameras (for example). Nearby is BIC camera, with a similarly large offering. Film prices err on the expensive side, and cameras aren't really cheaper than the US, but the sheer range will fill you with geeky joy!

Some more thoughts here: