subjective, artistic expression
The poetic mode of documentary moves away from the "objective" reality of a given situation or people to grasp at an inner "truth" that can only be grasped by poetical manipulation. There are no characters
Expository documentaries speak directly to the viewer, often in the form of an authoritative commentary employing voiceover or titles, proposing a strong argument and point of view. These films are rhetorical, and try to persuade the viewer. The commentary, also knowns as voice of God, often sounds ‘objective’. Images are used to advance the argument.
Observational documentaries attempt to simply and spontaneously observe lived life with a minimum of intervention. The filmmaker remains hidden behind the camera, ignored by the surrounding environment he/she neither changes nor influences the actions/events being captured. Since nothing is staged for the camera, the camera rushes about to keep up with the action resulting in rough, shaky, often amateur-looking footage. There are usually no interviews in this mode.
Participatory documentaries believe that it is impossible for the act of filmmaking to not influence or alter the events being filmed. The filmmaker's impact on the events being recorded is acknowledged, indeed, it is often celebrated.
Those kind of documentaries are representations. The Reflexive Mode acknowledges the constructed nature of documentary and flaunts it - conveying to people that this is not necessarily "truth" but a reconstruction of it - "a" truth, not "the" truth. The artifice of the documentary is exposed - the audience are made aware of the editing, sound recording, etc.
filmmaker as a participant
Performative documentaries stress subjective experience and emotional response to the world. They are strongly personal, unconventional, perhaps poetic and/or experimental, and might include hypothetical enactments of events designed to make us experience what it might be like for us to possess a certain specific perspective on the world that is not our own. This mode of documentary emphasizes the subjective nature of the documentarian as well as acknowledging the subjective reading of the audience - notions of objectivity are replaced by "evocation and affect"