Principal Photography refers to the phase of film production during which the movie is actually shot, as distinct from pre-production and post-production.

Principal photography is usually the most expensive phase of film production and generally marks a point of no return for the financiers. While it is not uncommon for a film to lose its greenlight status during pre-production (for example, because an important element such as a cast member drops out), it is extremely uncommon for finance to be withdrawn once principal photography has commenced (and is usually regarded as a catastrophe).

Once a film concludes principal photography it is said to have wrapped, and a wrap party may be organised to celebrate.

During post-production, it may become clear that certain shots or sequences are missing that are required to complete the film, or that a certain scene is not playing as expected, or even that a particular actor has failed to turn in a performance of the required caliber. 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.