Hi from Greece ! I am an amateur and I want to upgrade my equipment so I need your advice. The lenses I own are : Canon 24-105 mm F4 L IS, Canon 70-200mm F4 L (non IS) . I intend to change the 24-105mm with Canon 28-70mm F2.8 L ( I found one used). I dont have the money to go for Canon 70-200mm F2.8L IS so I am looking for a prime lens for portraits. I know than the Canon 135mm F2 L is a very good lens and I can aford the money. I want your opinion . I also have the Canon 5D.