One more thing to know is that please please get a 3rd party hood. The lens AF mechanism is very fragile and any delicate amount push on the USM motor front protuding part will invariably damage the motor and it's ability to AF properly.
Also this lens doesn't use true USM. It uses micro USM. Be careful how you store this in the camera bag as well. Please use hood all the times or else this lens will fail on you sooner or later.
Terrific lens and very good creamy bokeh compared to nifty fifty. Not very sharp at 1.4 due to small DOF, but it's really good at 2.2 and really amazing at 4.0. Also good for people who don't want sigma lottery.