It took fast focusing to get this shot of a great egret flying almost directly over my head. I captured the image with the Nikon D4S and the 800mm f5.6 Nikkor. It was my first day of shooting the D4S and I’m happy to say that the upgrade from the D4 was worth every penny. I probably would not have been able to capture this shot with the D4. The primary difference between the D4 and D4S is a faster processor that enables faster autofocusing. The D4S also has a “group area” autofocus mode that the D4 does not. I was using it when I took this shot.