Power

Power is defined as "the capacity or ability to direct or influence the behaviour of others or the course of events", and photography is an inherently unequal medium. Yes the model has some power in how they choose to present, but it is the photographer chooses angle, focal length, exposure, and ultimately which motive to deliver.

 

The angle you choose does a lot to influence the viewers perception. I choose to portrait my subjects in a position of power, so that I influence the perception of the subject, by the viewer. That, is power.