I put in my pre-order today for the Fuji XF 100-400. I live in the Black Hills of South Dakota, surrounded by wildlife of all kind. I do a lot of shooting with two friends who are both Nikon shooters (I was for 40 years) and they have great long lenses - one has the Nikon 400 and Nikon 600 and the other has the recent Tamron 150-600. I sold all my Nikon stuff last year and have missed the long reach, but now I am going to be out in the field again with the bison, antelope, deer, prairie dogs, waterfowl and herons that live here in the beautiful Black Hills.