that shit happens to me too from time to time.. i always have to add a tad bit of sharpening in photoshop.. i know the 50mm is a sharp lens so im not sure what ya issue is there.. I know i have a 24-120mm and i get wicked lens flare with the lens wide open at a low f-#.. Adjusting your aperture helps from time to time.. you might want to check the in camera setting under shooting menu and see what you have your "optimize image" set on..