This lens, and Nikon's 200-400 f/4 VR...does not make a lot of sense for many scenarios. Oh sure, there are "some" people who want this focal length range, but to "me", I always thought the 200-400 f/4 was kinda useless. Why???
Let's just call the lens 7.5 pounds. Soooo, a 7.5 lb, 200mm f/4??? WTF??? Or a 7.5 lb 300mm f/4? Huh??? A traditional Nikkor 200mm f/4 is about the size of the bottom part of a 12-ounce beer bottle, and used 52mm filters. A Nikon 300mm f/4 AF-S is about the size of a 1-liter soda bottle, and is 'roughly' the size of a 70-200mm f/2.8. Basically, the user gets a long, heavy, FRONT-heavy, slow-aperture lens, for thousands of dollars...
Again??? A 7.5 lb 200mm f/4 lens??? F/FOUR????
Nikon's 200-400mm f/4 always struck me as a "so what!" lens...same with this thing. Of course, for daytime birding, and for some field sports shot during decent light, from stationary positions, and where nothing ever comes close to the camera position so that 200mm is not a drawback, and you do not mind being forced to work off a monopod at all times, then yeah, 200 to 400mm stuck at f/4 makes some sense.