I've always been an inveterate fixed focal photographer. Six months ago, I then but me - after much hesitation - bought this lens. I have then printed some objective test panels from the internet and compared with some test shots of this lens with my lenses. At 85mm, this lens has the same optical performance as the AF 85mm 1 in about 1.4. At 180mm, it is even more visible as the AF 180mm 1: 2.8. In practice (analog Railway Photography) I find the picture quality even better than that of 85mm lens. I submit that this lens is one of the few lenses, where the imaging performance can not be increased by stopping down. In short: I am absolutely thrilled with this lens and it can every single focal length photographers highly recommend.