I am looking to get either the Nikon AF-S 50mm f/1.4G SIC SW Prime Nikkor Lens (~$439) or the Nikon 50mm f/1.4D AF Nikkor Lens (~$329) for use as a fast focusing prime lens for the Sony NEX 6. Has anyone used this combination? What is the difference between the 1.4D and the 1.4G? From what I understand, the "G" is the newer lens, obviously pricer, and has AF-S. My question is if the AF-S feature is driven by the electronics specific to a Nikon camera body. Will this autofocus on the NEX as well? I am confused, and would appreciate if anyone can clarify. Obviously if this is true, there is no reason for me to buy the "G", as the benefit is specific to Nikon bodies only. Also, I would obviously need an adapter, can anyone recommend one? I am seeing ones that are offered with aperture control rings...is that needed/recommended? Your advice would be greatly appreciated.