[Editor's Note: This post was written by Bruce Logan, ASC, and originally appeared on the Zacuto blog. An edited version is republished here with permission.]

Nothing speaks more to your professionalism than the way you conduct yourself on set. I can’t tell you how many times I have cringed for certain crew members who, out of ignorance, made totally inappropriate comment in areas that they have no business being. The running of a professional motion picture set is a high-pressure, high-stakes endeavor. Knowing how to conduct yourself in the job that is assigned to you is of the utmost importance in being recognized as a working professional. Here are six rules for keeping yourself in check on set.

1. Mind your manners

There are some “common sense” faux-pas which should never happen. Like the Art Department Assistant looking over the director’s shoulder and saying that he didn’t think an actor gave a very realistic performance. Or the Data Wrangler sitting behind the director and department heads in dailies commenting on the way a particular shot is framed. No, no, no, no, NO! But, you’d never do that anyway! Right?

2. Actors stay in front of the camera

One of the most visible and obvious errors in film set etiquette is the actor who “cuts” himself or herself in the middle of a take. An actor should never judge their own performance and never second-guess the director. The actor might not know the director's plan and could have screwed up a valuable take.

Of course, there's an exception to every rule. If you are the high dollar actor upon who’s star-power the movie is financed…I suppose you can say just about anything you want at any time.

Nowadays, almost everyone has an eye on the production monitor which has put the sole power to cut back in the director's hands.

3. Only the director says 'CUT'

In theory, the director is the only person that says cut. It used to be that the camera-operator could say it, but that was back when the operator was the only person who ever saw the shot before dailies.

The operator used to have great power back then because she was at the nexus of the filmmaking process. She was the only witness to the culmination of all filmmaking elements coming together; only she could see if the shot was hopelessly going awry. This gave her the power to say “CUT!” Nowadays, almost everyone has an eye on the production monitor which has put the sole power to cut back in the director's hands.

The exception to this rule would occur to ensure safety on set. If the First Assistant Director (who, incidentally, is considered the primary safety officer on set) sees that something is going wrong with the choreography of the shot, she is empowered to yell “CUT.” This goes also for the Stunt Coordinator. ANYONE who sees something dangerous unfolding on set is obligated to speak up. But even then I think: “LOOK OUT,” would be more appropriate than: “CUT.”

4. Save your comments until the end of the take

Now I don’t want anyone to get the idea that everyone needs to keep tight-lipped on set at all times. If your craft requires it, you must speak up at the end of the take if something was not satisfactory with your department’s end of the take. But knowing when things are acceptable is a very fine line.

For instance, a Sound Mixer is the only person listening to the audio. If a truck rolled by and ruined the take, she has to speak up. But if a truck rolled by in the background and she knows that with modern technology it can be filtered out in post, she should mention it as an FYI to her department head and then let it go. Only experience makes it possible for a mixer to know the difference.

Experience and unobtrusive efficiency are everything.

5. Take care of each other

The Script Supervisor also has a really tricky job in terms of knowing when to speak and when to shut up. A Script Supervisor, sometimes referred to as Continuity, is responsible for whether the shots will cut together without any mismatches. They are also responsible for the actor having said all the right lines in the script and for keeping track of all the coverage in the scene.

It would be easy to announce at every opportunity when an actor (or indeed even the Director) has made a mistake, but the Script Supers that I like whisper with the actors if they are holding a prop in the wrong hand, or talk individually with the Director and D.P. if someone’s eye-line has been crossed. There’s no need to call each other out on errors when a quiet, calm word will do. Experience and unobtrusive efficiency are everything.

6. Learn the unique rules of your set

All sets are different. Some are chatty, fun places where everyone is fooling around and no one seems to mind. Others are quiet, somber spaces for actors to do serious work in a safe environment in order to give heavy, award-winning performances. Take your lead from the department heads, starting with the Director and the First Assistant Director. If in doubt, don’t say anything unless it is to your immediate supervisor and directly about the job you are doing.

Follow these rules and with a little experience, you can have fun doing your job, blend with your environment, and you will soon be appreciated as the consummate professional.

Visit Zacuto.com for more great filmmaking tips. Bruce Logan, ASC was born in London. His love of imagery started when he was hired by Stanley Kubrick to work under Douglas Trumbull on '2001: A Space Odyssey'. He came to California in 1968 and worked as a DP on over a dozen films, including: 'Tron', 'Star Trek', 'Airplane', 'Firefox', 'High Road to China', 'The Incredible Shrinking Woman', 'I Never Promised You a Rose Garden', 'Big Bad Mama', and 'Jackson County Jail'.