Your world-position to the woman does indeed not matter for the angle of the shot. It's randomized based on the lens that you are using and makes sure that you don't get the same shot twice. So, e.g., a normal lens will give you a random panty shot (with a slim chance of being an extra rare special photo), but from where you took the picture does not modify the outcome.
More variation comes from the different lenses, and once you have unlocked hypnosis lens, you also have different body shapes with three different butt-sizes to explore! :)