Lacy & Kevin asked me this question a while back:
What's your take on making a short film as a means to getting your writing out there?
Even if it's well filmed, are you better off querying, or do you think it's a waste of time?
I think it can be useful, but you're better off if there's a clear hook to the idea. That might mean that doing the short film version of your feature script might be problematic. Instead, make sure you choose a premise that makes the best use of the medium.
One of the best examples of this is the short film George Lucas in Love. Written by Joe Nussbaum, Timothy Dowling &Daniel Shere, and directed by Nussbaum, the film was produced in 1999. This was right at the time that anticipation was building for the release of Star Wars: Episode I - The Phantom Menace, and also right around the time that Shakespeare in Love won the Oscar for Best Picture. The creators saw an opportunity to make something timely that would get them noticed and have a built-in audience. If you're interested in finding out more about the film, check out this interview.
The film was later released on DVD, along with a behind-the-scenes documentary. In it, the creators talk about sending the film to all their contacts in Hollywood, only to return home one day to get a call from one of Steven Spielberg's assistants. It seems that a copy of the film ended up being passed all around Hollywood. It made its way to Spielberg's office and the assistant recounted how they gave it to Spielberg and heard him laughing as he watched it. Then the assistant was tasked with putting Spielberg through to George Lucas and heard Spielberg rave about the film to Lucas.
Nussbaum went on to direct the feature films Sleepover, The Naked Mile, Sydney White, Prom and is currently attached to Brad Cutter Ruined My Life... Again.
A more recent example is Kevin Tancharoen, who directed a Mortal Kombat short as sort of a calling card for what he'd like to do with the property. This was probably a smart move, because his lone feature credit - Fame - probably would have kept him in "Movie Jail" for a while otherwise. Instead, it landed him a job as the director for the feature version of Mortal Kombat.
Check out an interview with Tancharoen here.
I'm sure those are far from the only examples. I also have to assume that there are people who have gotten some notice from shorts that have placed in film festivals. I have to admit that I don't keep much of an eye on that world. If anyone has further examples, free free to bring them up in comments.
The internet is littered with "calling card short films." Sometimes they go viral, sometimes they don't. So long as you're not reaching beyond your means, I'm all for taking a shot at it.
