Launched in 2013, the 800mm f/5.6 is the longest and most expensive lens in Nikon's current line-up. So if you want the bragging rights on your wildlife trip or at an air show, this is the lens for you.
What else do we need to say? It's totally awesome in every way. If you need it, you need it, and you know who you are.
The lens is supplied with a dedicated TC800-1.25E ED Teleconverter. When used with this teleconverter, the lens becomes 1000mm f/7 and it will only autofocus with cameras which offer f/8 AF support, i.e. D4 series, D800 series, D750, D600 series, D7200, D7100.
COMPATIBILITY NOTE: The "E" in the name of the lens means it has an electronic diaphragm control. Only cameras introduced since about 2007 can control its aperture; with older cameras you'll only be able to use this lens wide open at f/5.6. It is not fully compatible with the D2 series, D1 series, D200, D100, D90, D80, D70 series, D3000, D60, D50, D40 series, or 35mm film cameras. And if you have a newer camera which is compatible, make sure you're using the most up-to-date firmware.
We appreciate this is complicated, so if in doubt please don't be afraid to ask.