I watched High Plains Drifter the other day, and then read on Wiki that the film’s production crew constructed the entire town on the shores of Mono Lake.
I would assume the film crew didn’t have access to electrical power from the grid. So how did they supply power to the camera and lights? A generator would be the obvious choice. But a generator makes a lot of noise, and would surely be picked up by the microphone.
So when making a movie in a remote location, how is everything powered? Do they use batteries to provide power to the lights and camera and sound equipment, and then charge the batteries using a generator between takes?
I’m not a filmmaker, but there are big semi-trailer generators you can get which you could position 500 yards away and run some cables. The microphones used are probably fairly short-range and directional, so they wouldn’t pick up a thing.
Plus, lots of the sound in movies is recorded in studios and added in later. Including dialog when ambient sound interferes.
95-99% of the sound mixdown comes from sources that aren’t recorded on-set. Even a lot of dialogue gets re-recorded in the studio after shooting because of sound issues on-set. It’s no big deal. It’s called ADR.
Lip-syncing and ADR are almost opposites. In lip-syncing, a performer is adding visuals (dancing, pretend singing) to pre-existing audio. in ADR, it’s the reverse – the performer is adding audio to pre-existing visuals. This means they can watch a short loop of film, consisting of maybe just a few words (hence the name “looping”), and say their lines in the studio over and over until they match just right. Also, the sound person can slide audio around a little bit to better match up with the lip movements if needed.
All this is 100% true, but to my ears looped studio-recorded dialog is always *incredibly *obvious. It never sounds like ambient speech in a natural environment, it sounds perfectly crystal-clear like a radio DJ in a booth (which, essentially, it is!)
To echo (hah!) what friedo said, it’s hard to notice when you don’t notice something. Any production worth its salt will record “room tone” (the ambient background noise of the location where they’re shooting) before finishing up at any given location. The sound people mix the ADR recordings with the room tone (and do a bunch of other stuff) so that the actors do not sound like radio DJs.