4. Principal Photography
This should start when principal photography ends with even a little bit of overlap in order to check the shots etc and get a basic picture lock before the wrap stage of production.
The bulk of this stage will be reviewing the footage shot, assembling the edit and also will include time for VFX, graphics and sound design and mix etc.
Once this is finished the project has final picture lock and you can begin to create the various delivery formats needed such as a Digital Cinema Package.