DXO rates it a lot higher than the Canon 35mm L. Even though the Canon has higher resolution, lower distortion, and about the same viginetting. The 35mml does have more CA, but that is because its f/1.4.Somehow, DXO seems to give CA a huge weight, unless you are looking at Nikon lenses with super high CA's and then it doesn't seem to count at all. http://www.dxomark.com/index.php/Lenses/Compare-Camera-Lenses/Compare-lenses/(lens1)/342/(lens2)/797/(brand1)/Zeiss/(camera1)/483/(brand2)/Canon/(camera2)/483