EDITED: How do directors film a conversation?

Some of the main rules in a conversation are the 180 degree rule, shot/reverse shot, rule of thirds and nose room/head room. The 180 degree rule is that when two people are having a conversation there will be a imaginary line between their eyes where the camera shoots them from. Shot/reverse shot is when you have a character looking at an object then a shot of the object and when the camera is back at the character they are still looking at the object. 

The rule of thirds is when there is 9 boxes across the camera and the characters eyes and face will be in line with the lines or sometimes jot in line, this will crate a sense of that character is off the rails. Nose room is when you have space in front of a character so they have room in front of them. Head room is how much space there is above the character and if there head has been cut off or if it is fully in shot.

Tips for filming a conversation are you have to have shot variety so that the viewer doesn't get bored with the scene and have a lot of ECU's and other shots like that to show emotion in the conversation. Another tip is to have a over the shoulder shot to show people are talking to each other.

In the clip, Gus and Walter are talking and at 1:04 Gus has been given a lot of nose room because it shows how cautious of Walter he is and how he doesn't trust him. At 1:32 Walter has a lot of head room and nose room. This shows how isolated he is at the time as he is begging to work with Gus and has no power at this point. 

In this clip, Dexter is talking to a police officer about the crime scene they are investigating. Throughout the scene even though dexter is waling around there is still a 180 degree rule as the camera always stays the same side of them. At 0:41 Dexter has lots of nose room as he is the one in charge of the situation and he is the powerful one in the scene.