For anyone shooting with a NEX that has Sony lenses, I highly recommend this adapter. Got mine in yesterday. I hooked it up to my NEX-5 (firmware update required) and fired away with a screwdrive 35/1.4G, SSM 24/2 Zeiss and even the 24-70/2.8 SSM Zeiss with full, fast AF. The array is impressive too with 3 cross type sensors and a more advanced AF module than the A900. It works great during video too.
LA-EA2:
Sony A-Mount Lens to NEX Camera Mount Adapter LA-EA2 B&H Photo
I have the LA-EA1 also, but it allowed aperture adjustment and some very slow AF with SSM and SAM lenses relying on the NEX CDAF. The EA2 adds a translucent mirror and new AF sensor array and essentially converts the NEX into an SLT. The EA2 works with SSM, SAM and screw drive lenses.