Without doubt, this lens is one of the more controversial lens than any other Canon lenses. For some reason, Canon decided not to include Close Range Correction (CRC) into the design of this lens. What happens is that when used at very close distance, this lens will back focus when stopped down, consistently. The more you stopped down, the more severe the back focus will be. I think that for an L lens with such a high price tag, it's inexcusable.

But, once one gets to know the lens, you just won't want to take it off your camera. I have had this lens for only a week, but I have already getting much better keepers than when I first used it.

Optically, this lens is amazing, just like the 85mm f1.2L. Both have amazing bokeh. Wide open, it's already very sharp in the center of the frame. The large aperture that creates the atmosphere is very difficult to duplicate with slower lenses. In fact, you just want to shoot wide open as much as you can.

To me, it's a keeper. Yes there are more throw away pictures with this lens than others, but I love it any way.