Short conclusion: average lens for bokeh, but very sharp stopped down.
The lens has very clean optics, and judging from the relatively large rear element, it's pretty certain the focal length is 50mm, with an aperture between f1.7 to f2.0.
It's too bad the bokeh doesn't excite me. I was hoping for a better lens. Oh well, at least it drove me out to take pictures :)
Lighting Fixture - wide open
View between two buildings - possibly f5.6