You know, I've had a couple of those "ultra fast" lenses. Without exception, the only reason I could find to use them wide-open is to get a photograph that cannot be made any other way - that is in very low light. The 50/1.4 Zuiko at 1.4 was soft and mushy around a semi-sharp central zone, and all the highlights had reddish halos. The 50/1.2 Canon in Leica m39 was just lousy wide open. The 50/1.2 Nikkor wasn't much good either. The 50 1.4 Nikkor was by far the best of the lot, but I sold the camera it was on - the original bill of sale said it and the camera were a unit. I now use the 50/2 Nikkor H lenses as my fast 50s, they do everything I need done, and have none of the aberrations (wide open) the faddists go gaga over.
Originally Posted by jstout