The 200-400mm f/4 VR is an awesome feat of engineering.It's focuses as quickly and as accurately as a big telephoto prime, and optically it's about as good as you could imagine in every conceivable dimension.Nobody else makes a lens like this, and it's definitely one of the highlights of Nikon's range.It's perfect for wildlife and great for sports.It can be used hand-held, but a tripod or monopod is recommended.

This lens works well with Nikon Teleconverters. The 1.4x Teleconverter makes it a 280-560mm f/5.6 lens which will retain autofocus on all compatible cameras. The 1.7x Teleconverter makes it a 340-680mm f/7-ish lens, and the 2x Teleconverter makes it a 400-800mm f/8 lens, but these latter two combinations will only autofocus on the D4, D600 and D800 cameras.