One of the great options associated with the Sony NEX (3 and 5) is the ability to use "legacy lens". A legacy lens is simply an old lens; brand really dose not matter in that "adaptors" are being made for most every lens out there. There are thousands of images posted on the NEX forums shot with Leica, Contax, Olympus, Minolta, Pentax and of course Cannon and Nikon glass. And most shots are outstanding!
About six weeks after getting my NEX-3 a ordered the Nikon F adaptor from Adorama in that I have several Nikon lens. The newest Nikon "G" lens won't work because they don't have an aperture ring. All lens used with any adaptor must be manual focused.
Using my old Nikon lens on the NEX-3 has opened up a whole new world of fun for me! Not only can I go back and use otherwise obsolete lens but the results are beautiful!
These shot were made with an old Nikon 50mm 1.8f AIS. This lens can on a Nikon F3 I had in the late 90s.
Yes, I can use this lens manual focus on some current Nikon bodies, but what makes the NEX combination so great is "manual focus assist".
More about that later.