This is said to be the world’s best lens for system cameras. It’s the just announced Zeiss Otus 85mm f/1.4 which comes with Nikon mount (Click here) or Canon mount (Click here) at BHphoto. But being a manual focusing lens it can be better used on a mirrorless camera with focus peaking and other helpful features Canon and Nikon do not deliver yet. The real problem of that lens is as you can guess….the price :)
P.S.: Image samples can be seen on Flickr.