I'm sure I'm going to get shouted at for daring to give this superb lens anything less than five stars but I really would caution potential buyers to think very carefully before organising finance for this substantial investment.
Firstly, there is no doubt that the 200-400mm f4 is a fantastic piece of lens design and offers quality close to that of the f2.8 prime lenses in a constant aperture zoom lens package, now with AF-S and VR. However, having worked with both this lens and the excellent AF-S 300mm f4 I have serious doubts about the extra capabilities of this lens over the 300/4, given that it now costs nearly SEVEN times as much and weights nearly TWO AND A HALF times more!
Particularly when travelling on foot or by mountain bike, the 300mm f4 was always a much more practical choice. Given its immense size and weight, it was hard to take anything else once the 200-400mm and a camera body had been packed in its custom rucksack. It would also be very hard to say that the quality of the resulting images ever suffered from the 200-400mm being left at home! In my experience, image quality from the 300mm f4, unencumbered by the need to provide a zoom range, is every bit as good as the 200-400, despite their huge difference in price and size. In all honesty I always took better pictures with the 300mm f4 and have the images to prove it!
Of course, the 200-400mm f4 has the ability to zoom back to 200mm and out to 400mm. Although this seems quite an impressive 2x zoom range, large changes in focal length have less effect at this end of the range. More importantly, what you actually see through the viewfinder is governed by the angle of view which the lens presents. The 300mm f4 has an angle of view of 8.25 degrees on an FX body. Zooming back to 200mm only increases this to 12.4 degrees and zooming in to 400mm only reduces it to 6.2 degrees. There's no denying that in many areas such as sports and action a zoom range is all but essential but these tiny angle differences can hardly be worth the immense difference in price. If I was feeling cheeky, I could say that the 200-400mm was basically a 200mm lens which allowed you to crop the image a little...
The VR facility was rarely useful to me as I generally photograph fast-moving subjects where a shutter speed well over 1/400th of a second was used. In addition I was almost never bonkers enough to use the lens handheld.
Don't get me wrong, the Nikon 200-400mm f4 is a masterpiece of optical design. Its speed and optical quality are as good as almost any other Nikon lens. My concern is that, for the vast majority of photographers, there are other lenses which will get the job done to a similar standard for a great deal less money, size and weight. There seem to be several `niches' where the 200-400mm f4 reigns supreme such as wildlife, insects, nature, surveillance and some sports. Unless these are the central areas of your photography, I would look very hard at how much the 200-400 is actually going to open up your photographic horizons over the excellent 300mm f4 AF-S, bearing in mind that most photographers buy their entire outfit with less than the DIFFERENCE in price between these two lenses!
For me, it wasn't worth the difference in value and after about three years I sold my 200-400mm f4 , bought two superb prime lenses (180mm f2.8 and AF-S 85mm f1.4), put a big slice of money back in the bank and reduced my house contents insurance premiums. I never miss this lens.
