This Polish site has got around to reviewing this lens. Panasonic LUMIX G 20 mm f/1.7 ASPH. review - Introduction - Lenstip.com A quote from the conclusion: This summary will be very short. Of all the lenses designed for mirrorless cameras (not including rangefinder optics) I like the Panasonic 1.7/20 the best. It is small, handy, fast and very sharp at all apertures. You can hardly ask for more.