Are you talking about the 50mm? The 50mm 1.2 is an L-series lens. It has “better” optics and weather proofing. It’s also better built. It’s also heavy! The 1.4 is an excellent lens. I wouldn’t spend the extra money if you are on a budget. If this your only prime, i would get something a bit wider, like an EOS 28mm 1.8 . You can use this lens in almost any situation. I think it will be more useful. 50mm on a 7D has a very narrow field of view and limited use in my opinion. It all depends what you are using it for.