I'm a newbie and i'm keen to explore macro but not ready to spend so much on canon macro lenses. I'm also hoping to shoot full body portrait with shallow DOF but couldnt really do it with my canon EF 50mm f/1.8. My friend recommended that i should get Sigma 70-300mm APO DG macro. Has anyone tried this lens before? Can you tell me the pros and cons of it? Thanks!