A documentary film is intended to be much more like a piece of journalism than a piece of entertainment or expressive art.

There is typically a voice-over narrative going on throughout a documentary film with the narrator describing what's being seen in a businesslike way without any dramatic reading.

Documentary films are often made to more deeply explore a current events or history subject that has remained shrouded in mystery, been controversial, or in the opinion of the film maker misunderstood or underexposed.

Documentaries have also been made simply to record an event of personal interest to the film maker.

Biographies, sports and music events, a compilation film of collected footage from government sources, and so on and so forth all may be subjects for a documentary film.

Documentary film makers are typically the writers, directors, and producers. Often they may act as cameramen as well.

Documentary films are most often made for TV but in more recent times there have been more of them made as direct-to-video, made-for-video, straight-to-video, or straight-to-DVD formats in which they were never first played on TV or in the theaters but were simply distributed for home-viewing.

Some major motion pictures when released in DVD format also come with bonus DVDs that act as documentary films of the making of the movie.

Documentaries also often feature re-enactments of events that could not or were not originally documented on film such as historical events from the year 1776.

There have also been "mockumentaries" made, in which a piece of comedy fiction is made but is done up in the same dry and straightforward format of an actual documentary. "This Is Spinal Tap" and "The Gods Must Be Crazy" are two of the most successful mockumentaries ever made.

To put together a quality documentary film, the filmmaker first begins by doing research, even if he knows the subject matter well already.

The Main point of a documentary film is to relay facts and information from all angles.

Quality documentaries usually include interviews at some point. This is a technique for lending authoritativeness to the film's producer by getting people to speak from first-hand knowledge about the subject matter or an aspect of it.

A documentary film also has to be well organized in an interesting and logical format.

Unlike with many fictional movie stories, a documentary should never deliberately confuse, mislead, or leave something mysterious.

Multiple perspectives or opinions can be highly effective at giving a documentary film depth.