It's rather incredible that we can get a telephoto lens with double the speed of a pro 70-200, in this ultrasmall package! It's the same size as a Nikkor 50mm/1.8! Already wide open it is really sharp, but a bit lower on contrast due to spherical abberations. Which suits portraits just fine, by the way. From f/2.8 and up it is supersharp and contrasty, and as good in all aspects as any other comparable Nikon tele, including the 85/1.4 and 105/2.5

Very difficuly to nail the focus, but that goes for all manual teles.