Conventions Of A Short Film

From my preliminary research i have found many common conventions of short films. They are usually between 5-15 minutes in length. There will usually only be main characters and no secondary characters as the film length is too short to establish these secondary characters. There is a maximum of 3-4 characters for each film as there would not be enough time to establish these characters in the length of the film. I have also noticed that some of the short films tend to have a twist at the end. This makes the film engaging for the audience. A typical budget for a short film can be anything from $100 - $10000 but will typically be somewhere between those two figures. Due to the small budgets of films there tends not to be much cgi in the film and they will usually be shot on dslrs.