EDIT: On the other hand, this is Feng Zhu we're talking about. Maybe he was determining what kind of "lens" his viewpoint would have. For instance, and I'm talking over my head here, the human eye is supposedly the equivalent of a 50mm lens. I know different lenses distort the perspective in different ways, but I couldn't for the life of me tell you which one does what.
Technically he is referring to two parameters under the umbrella term "camera":
- viewpoint position (high/ low, looking up/ down)
- focal lenght (the closer the vanishing points are, the shorter the lens (and the stronger the distortion))