Nikon makes three different teleconverters or extenders. Teleconverters are an easy way to get extra reach out of telephoto lenses as long as you understand the drawbacks. Also, make sure the lens you want to use one with will mate with teleconverters as not all lenses do.
The 1.4x multiplies the focal length of your lens by 1.4, adding an additional 40%. So a 200mm lens becomes 280mm but at the cost of one stop of light. So an f/2.8 lens becomes f/4.
The 1.7x multiplies the focal length of your lens by 1.7, adding an additional 70%. So a 200mm lens becomes 340mm but at the cost of one and a half stops of light. So an f/2.8 lens becomes f/4.8.
The 2.0x multiplies the focal length of your lens by 2.0 adding an additional 100%. So a 200mm lens becomes 400mm but at the cost of two stops of light. So an f/2.8 lens becomes f/5.6.
Optical Conversion Factor
Effectively increases the focal length of the attached lens by 70%
FX in DX Crop Mode
AF-S (Silent Wave Motor)
(Approx.) 2.6x1.2 in. (Diameter x Length)
66x31.5mm (Diameter x Length)
(Approx.) 8.8 oz. (250g)