I'm trying to avoid adapters. The Ziess is autofocus. An A-mount lens will also autofocus on a NEX, but only on an appropriate adapter, adding to weight and size. And for this focal length, its the compact size and general portability that is key. I'm pretty sure over the next year or so we will see a rash of new E mount lenses from Sigma, Tamron and possibly a few more from Sony and Zeiss. For now, the Ziess 24mm looks the best bet for a compact, high quality autofocus general purpose lens. Hopefully I will receive it soon and will report back when i can test it out.