Multiply your lens' focal length by 1.7x with the Nikon AF-S Teleconverter TC-17E II for F mount lenses. This teleconverter will maintain full metering and focusing with compatible cameras and lenses, and will also support the VR function found on many current lenses. This teleconverter also has Nikon's Integrated Coating to limit flaring and ghosting that may occur.
Many such teleconverters can also have a detrimental effect on the speed of the lens, however the AF-S Teleconverter TC-17E II makes only accounts for 1.5 stops of light loss.