I currently print my images using a 3:2 ratio of 12 x 18, 16 x 24, etc., which gives me the full image captured by my cameras (D7000 & D600). I looked at the print sizes of many professional photographers and some use 3:2 or 4:5. Can anyone explain why some choose 3:2 vs. 4:5? Also, how do you compose an image different when shooting 4:5 vs. 3:2?