The Voyeuristic Approach: choosing a long lens

I was reading a few weeks ago about focal lens as an analogue of actual distance. My notes tell me that was in a book edited by Elizabeth Edwards called Anthropology and Photography, p. 162. The telephoto lens lends itself to a voyeuristic appeal, with its perspective and shallow depth of field, the distance between the photographer and subject is evident. The question is when one might use it. I’m wanting to draw more and more parallels between colonial photography and the viewing of the subjects and the work I’m doing now, looking at these tribes disenfranchised by the British and maintained by independent India up to the present day. I’ve been thinking a lot about doing a series of colonial portraits as a branch from the main documentary. That’s definitely happening. I’d like to take the voyeuristic approach to some aspects of the culture too. But I’ll find out what in a few days.