I had long wondered whether I should buy a telephoto for Sony NEX, or whether I should upgrade my GF1 again. The NEX is the sensor clearly superior, but Sony builds're sorry, but no really good optics. (Except the E1,8 / 50 OSS) After seeing at Photozone test photos of both manufacturers, I could decide only on the Panasonic H-FS045200E. I have not looked back.