Hi bro, it actually depends on what camera body you're using. Different body and lens combination will give different results. As you know, a 5D body (the one I'm using), will give different results when using a 85mm f/1.8 (the one I use to shoot portraits), as compared to a 50D with this lens.
So you have to read up and know how each body will behave with a particular lens before purchasing it.
can i ask what lens u used to take those portriats pictures of the model which u newly posted? im newbies and thought of getting new lens for myself but just do not know what is good, so saw ur shots and i like that kinda results, or perhaps u can advice what lens is good for portraits shots?