I just received my first non-stock lens for my NEX-5, Konica Hexanon AR 50mm F1.7, that I buy from ebay.com.
I use Fotga Konica-NEX adaptor to attach the lens to my NEX 5.
Attached to NEX 5.
Some sample photo taken using the new lens:
The bokeh effect is quite nice.
Large F1.7 aperture do performed better in low light condition.
More photos using this lens.