many people like to take photographs during  favela visits - this is perfectly acceptable, but must be approached with a sensitivity and awareness that takes into account the experiences of locals.

one must consider how residents of favelas will feel about themselves and their communities being the 'subject' of photographs - visitors should not take photos of people unless they are expressly invited to do so by the individuals in question. 

similarly, no photographs should be taken of children, people at work, people taking care of their homes, performing domestic work, business transactions, or the interior of homes - to photograph without explicit consent would invade people's sense of privacy and personal space, and objectify their lives.