Defining the lines between porn and fine art photography

Its more often than not asked whether nudity images in  fine art photography are considered of a pornographic nature.This post will consist of my views on why i feel like these two genres are very much worlds apart in terms of how you view the image and its composition and how you portray the model and meaning behind the photograph.Above are two images taken from Terry Richardson  book Terry's world,They consist of a vast about of explicit images in a explicit manner. While interesting to look at from a photography aspect, defining the meaning of what category this actually filters into , for me i feel is easier to categorize.The two images below are from the current series of images I've shot with Polaroid which also display nudity but in a manner which is more of a fine art aspect.Its obvious statement to make that the thing they both have in common is nudity but the way a photographer shoots and frames an image.The structure of whats been shown and how the photographer proposes to show the model structure and body frame with pose.Reasons why i think they are considerably different is sense that i think Terry  Richardson objectifies his subject in and explicit manner with the view  to be seen as a arousing and pleasing image.Using intense light to highlight the subject matter in a prerogative manner where as i think my images are fine art images with a combined fashion element with the thought process being to explore the subject it a more delicate manner and  emphasis bone structure and body form rather than sexual preference .