In the best case scenario, a producer does as little as possible on set. Because if they’ve done their job, everything has been prepared in advance. But let me back up.
I like to joke that producers do a little of everything and get none of the credit (except maybe when there are bills to pay or an award to accept). But seriously, all of the decisions about what a movie is about, how it will be made and who will see it are filtered through the producer’s office. Producer's carry the vision through the vicissitudes of production.
Even in the case of a writer-director who has done the lion’s share of creative work, the producer can have a guiding hand on the wheel. We critique story points, express budget concerns, and double check production plans. At the very least, the producer is a sounding board who also provides checks and balances.
It’s the producer’s job to make sure the director and crew get what they need to execute the production, but we must set limits and spell out objectives. There’s never enough time and money to make a movie, whether you are a tadpole independent or a tentpole blockbuster. So you have to plan, be prepared, and make the difficult choices when the inevitable problems arise.
The producer sets the tone for the production. I try to treat the director and crew the way that I’d like to be treated if I was behind the camera. That means a well-run set, where everyone feels appreciated and taken care of—and the drama is all in front of the camera.
And if that’s done properly, the producer has very little to do on set. As it should be.