When you are capturing dialogue in a marina or most busy city places, is it good technique to boom from above and capture or is it ok to point the shotgun at the talent? I think I have seen it both ways and I am working on a student film right now. The dialogue has a lot of off axis noise and probably due to improper booming technique but I wanted to ask here.
General rule is boom from above and point directly at the talents mouth and get as close as possible without being in frame. The reason is that the body of the talent will block a lot of noise. If you point a mic directly from front or to the side of the talent then you run the rise of booming the background if the mic goes off the talent. This isn't such a problem from above as you will be technically booming the ground. A good shotgun mic should minimise the background to an extent, but alway do an atmos track for the editor to work with, especially in a nosier environment.
Always try and boom from above with the mic pointed at the mouth of the actor who is currently speaking. Students, sometimes, incorrectly try to place the mic where it can pick up two actors at once, rather than memorise the dialogue so that they smoothly move the mic from character to character.