Claim: Prometheus is a film.

thumb | 300px | Film production on location in Newark , New Jersey , April 2004 .   Principal photography is the phase of film production in which the movie is filmed , with actors on set and cameras rolling , as distinct from pre-production and post-production .   Principal photography is nearly always the most expensive phase of film production , due to actor , director , and set crew salaries , as well as the costs of certain shots , props , and on-set special effects . Its start generally marks a point of no return for the financiers , because until it is complete there is unlikely to be enough material filmed to release a final product needed to recoup costs . While it is common for a film to lose its greenlight status during pre-production -- for example , because an important cast member drops out -- it is extremely uncommon for financing to be withdrawn once principal photography has begun .   Feature films usually have insurance in place by the time principal photography begins . The death of a bankable star before completing all planned takes , or the loss of sets or footage can render a film impossible to complete as planned . For example , sets are notoriously flammable . Furthermore , professional-quality movie cameras are normally rented as needed , and most camera houses will not allow rentals of their equipment without proof of insurance .   Once a film concludes principal photography , it is said to have wrapped , and a wrap party may be organized to celebrate . During post-production , it may become clear that certain shots or sequences are missing or incomplete and are required to complete the film , or that a certain scene is not playing as expected , or even that a particular actor 's performance has not turned out as desired . In these circumstances , additional material may have to be shot . If the material has already been shot once , or is substantial , the process is referred to as a re-shoot , but if the material is new and relatively minor , it is often referred to as a pick-up .