Just a couple things to be aware of with the lens. It gets soft wide open and slightly at full 500mm extension. I tend to use it in Aperture priority mode at f8 or f9 and make sure that my ISO allows me to shoot fast enough to capture them in flight (1/800sec or faster). It works great on the D600 because the high ISO performance is spectacular. On the D800 I'll set it to DX mode if only to save on file sizes, but I'll shoot FX on the D600.