Originally posted by anirbax I had the same dilemma once -- if you are looking for sharpness and contrast wide open and don't mind manual focus, stick with the SMC-A 1.7. If you need fast AF go for the FA 50/1.4 (which is great stopped down to 5.6, but which lens isn't?).
I had the same problem as anirbax and I solved it by getting both!
Along with the M 50/1.7 and SMC Takumar 50/1.4 and I got a K 55/1.8 just to be sure I wasn't missing something, lol.
I guess I love Pentax 50's.
It would be really hard to pick a favorite, the FA 50/1.4 is always with me just in case I NEED the f1.4 and the AF, it was my first new quality prime that I bought after I got my K10D and it has never let me down. But there is something about the way the A 50/1.7 renders images, the colors, I can't explain it but I like it.