Two frequent ways a second unit is used are: In both of these scenarios, the purpose of the second unit is to make the most efficient use of some of the resources that are expensive or scarce in film production: actors' and directors' shooting time, sound stage usage and the cost of sets that may have been built on stages.
"[2] Brett Ratner, commenting about Conrad E. Palmisano, who directed second unit for him on multiple occasions said, "He has the understanding of what it takes to create a great action sequence and never deviate from the story or the tone of the film.
Some directors, such as Christopher Nolan,[4] Quentin Tarantino,[5] Paul Thomas Anderson, Mike Judge, and Stephen Hopkins, do not use second units in their films.
An example of this is Robert Shaye, who directed the melting staircase sequence of Wes Craven’s A Nightmare on Elm Street, which he produced, as well as having two uncredited voice roles as the television newsreader and the KRGR radio broadcaster.
Sometimes, actors get a start serving as second unit director, like Danny McBride, who served as second unit director for David Gordon Green on George Washington, before making his acting debut in Green’s next film, All the Real Girls.
He served as stunt coordinator on Four Brothers, Shooter, Dawn of the Dead, and Total Recall, but Doug R. Coleman, Jeff Habberstad, Clay Staub, and Spiro Razatos respectively directed second unit as opposed to Stoneham, Jr.