Here are a couple of links to the Sigma 30mm and 19mm lens reviews:
SLRlensreview (Click here) tested the 30mm lens on the Sony NEX camera: “Sigma’s entry level prime indeed bests Sony’s lens in resolution department. Everything else seems to be very comparable. So the recommendation is to choose Sony’s E 30/3.5 if you’re into macro photography, while for everything else just go with Sigma’s 30/2.8 EX DN.”
30mm first look at Photographybay (Click here): “So far, the Sigma 30mm f/2.8 EX DN looks like a real winner for Sony NEX cameras as a fast walkaround lens.”
Another 19mm lens test on the NEX-5n can be seen within a forum post at Fred Miranda (Click here): “I think this little lens holds it own, with a muted contrast/high detail rending all it’s own, excellent ergonomics, and a ridiculously low price.”
Also Photographybolly (Click here) is testing the 19mm lens: “In conclusion, for $200 this lens is great value for a very good lens. If you already have the 16mm you might decide to give this lens a miss. If you don’t, having used both, I would recommend the 19mm over the 16mm.”
The 30mm lens is in Stock at Amazon US (Click here), Amazon DE (Click here), Amazon FR (Click here).
The 19mm lens is in Stock at Amazon US (Click here), Amazon DE (Click here), Amazon UK (Click here), Amazon FR (Click here).