Just fantastic. You've heard the term "plastic fantastic" before? Never has it applied to a lens so much as with this beauty.
I've upscaled duplicates of blueprints to 24x36" at 300 dpi (75 Megapixels) with this lens and every single little detail is there. This must be the one of the sharpest lenses in Pentax's lineup, if not the sharpest.
And it's like $100.
< / sarcasm>