surprisingly I really see no need to upgrade the 50, unless I were to go for the 1.2-- which is a little out of my budget. I could care less about how fast the auto focus is, as I only use it for video. Also, even though a lot of people love this lens, I still think it's very overlooked. It's built like a toy but the glass is amazing. I take good care of my gear, so I'm not too concerned about how well the build is. Best 90 bucks I've ever spent