Let me explain my question/situation before I really ask it. I currently own a D800 which I've used for weddings, portraits, birding and various wildlife photography. I've always loved the images and detail, but sometimes have noticed pictures are bit softer than I want them to be, especially shooting birds in flight. Since most of my bird/wildlife pictures are from small boats, I can only hand hold my camera and lens which is a 300mm with TC20. I have calibrated my lens with camera multiple times and can produce some extremely sharp images with that combination, but have noticed that I also get a lot junk miss focused/soft images. So, I was curious to know what the group area AF in the D4s and soon to be released D810 have been like for people? Also do you all think the new focusing engine will help me? I'm not quite ready to jump on a D4s, which I'm assuming will be better at focusing than the D810, even with the same engine, but am extremely interested.
Any help would be greatly appreciated.