Quote Originally Posted by agw View Post
Okay, so I have and (more or less) regularly use the ZF.2 50/1.4, AF-D 50/1.4, and Ai 50/2. Among them, I like the ZF the most, and the AF-D the worst. Actually, my copy of the AF-D suffers from some "blue dot" phenomenon, where under certain (outdoor) lighting conditions and apertures a blueish circular haze can be seen in the image center. This is most noticeable on digital sensors, but can sometimes also be seen on color film. This makes this lens pretty much useless for me, except for indoors use.
That's interreflection between the rear element and the film/sensor. Doesn't happen with B&W films since they have a matte finish, but (glass) sensors and some chromes are nice and reflective. The Minolta AF 50/1.4 suffers from the same problem, which is why Sony redesigned that lens first-up when it bought the Minolta camera division.