Extremely sharp. On the d7000 and d80 that I used it with, the image quality was incredible with autofocus. It's an amazing lens for macro shots as well as portraits.
On the z50, it doesn't have autofocus since the motor is missing from the body, but with the built-in focus assist in manual focus, it doesn't bother me much. It was purchased for 450 euros a decade ago. I would only replace it with another Tokina lens with autofocus