Originally posted by str8talk83 I read photozones review of the 43 and it does seem to have some strange bokeh sometimes. I really like the look of the 77 images for portraits.
The Limited lenses aren't w/o their flaws. Like the FA43 which was rated poorly in the film days, but now very highly on digital. The thing is that back then we shoot film, and it shows more barrel distortion and not quite remarkable sharpness toward the edges. On APS-C, both issues aren't obvious because the outer portion is being cropped. Still, it is quite soft wide open. One stop down, sharpness is much improved. Also, this lens has bright ring bokeh yet with 3D quality (if you believe such expression). The bright ring bokeh might be annoying when the OOF background gets busy.
The border sharpness of FA77 is rather low until f4 on digital. It is also known to produce PF at high contrast edges. A taiwanese website tested it against the EF85/1.8 which beats the FA77 in every area optically. Still, it is one of the rare AF lens which MF nicely and pleasant to use, despite its flaws.
The FA31 is probably the rare gem from Pentax. It contains floating design and glass AL, both very rare for Pentax lenses. Optically it is good. The only issue is that the focus ring is kind of loose due to the way it was designed structurally. The rendering reminds me my old Sigma 24/2.8 which is both sharp and smooth. I have no such experience with any other Pentax lenses I have used, even the 3 EF lenses I have (but this is rather subjective).