The lens is just a fairy tale! I chose from several instances of test shots of the radial world. Mine is very sharp throughout the frame. Elka says it all. Top quality build! although the lens has dust and moisture protection, it is still recommended to install a protective filter. I put MARUMI UV WATER PROOF COAT with it, the lens made great friends))) it does not chromate or vignette. The picture gives a very sharp and juicy. Focuses almost instantly even in low light. I compared it with 16-35, I liked 17-40 even more in terms of color reproduction. I recommend to all!