Wow, that is a nice shot! Very nice and sharp! The backlighting really brings out the colors. I also like the composition, the leaf is not just smack-dab in the center of the frame. The background is nicely blurred, the 50mm 1.8 as good at that I hear! I think the picture could have been stronger if the background could have been all blue i.e. just the sky, instead of the other leaf which sort of blends in.
Overall, I think it’s a very nice picture, I would have been happy to get a picture like that!