Well, out of all the answers, those are plausible. But there's one possibility that many may not have thought of: Maybe Jeff didn't have any film in his apartment. Remember, he was in a leg cast for at least a month at most a few months. So, instead of having rolls of film lying around that could potentially expire and be useless to him, he probably sold off whatever unused stock he had to a couple of friends (we know he has some, especially with Doyle) or didn't order any new rolls of film like he normally would if he hadn't broke his leg.
Having to read the original short story by Cornell Woolrich, I don't recall the photographer aspect being in the actual short story. The binoculars is there, but I don't recall the character in the short having a camera. But then again, it's been years since I last read it.