If it is
this K-mount lens then, it might as well be the same design and glass as my Auto Revuenon.
My lens is a bit soft wide open but not that bad at all. However there is a major flaw which shows up pretty often: strong color aberration/fringing.
See the examples below, everything original, out of camera, only resized. Of course these are all the typical error-prone situations but this lens produces quite an extreme amount of fringing, see the blurred branches are just fring-brach-ings
P.S.: I am not sure at all that the Chinon is optically the same lens as the Auto Revuenon!