The Fisheye-Nikkor 6mm f/2.8 is the world’s most extreme wideangle lens with a viewing angle of 220º, it was unveiled at the Photokina trade show in Cologne, Germany in 1970.
It weighs an amazing 5.2kg, is 171mm long and has a diameter of 236mm. You can buy this lens for the low price of £100,000.
Via Nikon Rumors