After the expected announcement of the new Nikon Z 6 and Z 7 mirrorless cameras, Nikon has also announced a new super-telephoto lens for the existing Nikon F mount based DSLRs. The new lens is also compatible with the new Z series cameras using the new FTZ mount. The new super-telephoto adopts Phase Fresnel (PF) tech’ seen in the earlier 300mm F4 PF to reduce both the size and weight. It measures just 237mm in length. With one PF element and three ED glass elements – there are no fluorite elements – it weighs just 1460g, almost half the weight of the existing AF-S 500mm F4E ED VR. A lighter…