The #1 thing your subject wants is TRUST.
Defer all of your decisions to trust.
Ask yourself, "Will this break or strengthen the trust my subject has of me?"
Documentaries - and really all of human life - is built on relationships, and thus, trust.
Your word must be sacred.
If you capture footage that your subject asks you to not include in the film, there's multiple ways to handle this.
- Assure them it will not end up in the movie.
Because the footage is so unique that it should be held on to. Say everyone may feel differently many months from now, and it may be worth revisiting the idea. But for now they have your word: it won't be in the film.
- Give them the master tape containing the original footage.
Hand it to them. Say they have the only copy of the footage. If they wish to destroy it, they can. But remind them of how important and valuable the footage is, and how emotional everyone feels in the heat of the moment. Implore them to at least hold on to the footage for a period of time before making an irreversible decisions.
The idea is to put the subject in control of the situation.
You don't want them to feel like you're a sleazy exploitation filmmaker, running into town, taking their soul for nothing, then leaving to raise a buck.
Build trust with your subjects before anything else.
Take them out to lunch (you buy).
Get to know their family.
Find what you have in common outside of the movie.
Bestow them with gifts.