SMC Pentax A 50mm f2
I must admit that this is the first Pentax K series lens that I've shot with. I used Ricoh lenses when I was young. I expected this lens to image like a Takumar but it actually doesn't. In some respects it is better but it does have its minor faults.
This lens handles very well on the M3 mirrorless body. It is lightweight and easy to focus using the optional EVF finder. The aperture ring turns freely and it balances very well in hand.
It is tack sharp wide open with excellent contrast. It is sharp corner to corner. I'd say it is sharper than the 55mm f1.8 SMC Takumar. Bokeh is pleasing thru f5.6. Fringing is minimal and color rendition is very accurate.
So then, what's not so good? Flare. If you shoot in the general direction of the sun you will see a significant loss of contrast across the frame. If you shoot toward the sun you will get sharp, hexagonal flare. The build quality is a but disappointing too. The lens feels cheap.
Would I shoot with it? Absolutely Yes. If used properly this lens is capable of striking images and it feels comfortable in hand.