Continuity editing is just a style of editing to ensure a cohesive production through the edits. As far as number of cameras you should use is up to you. More cameras equals more footage to sort through to pick your best shots, but also gives you more footage to help cover mistakes like continuity. (i.e. person is holding glass in right hand in one shot, next shot of actor he is holding a bottle – continuity break! or say there’s a scene of a helicopter that has a retractable landing gear, it lifts off and retracts gear, but in the next shot, it’s moving away and the gear is still down – continuity break!) As far as background noise, you should record a sample of generic background noise at location before getting your other shots done so you have a background bed to use in smoothing out the audio. Hope this helps you out.
John
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