Extreme wide-angle Nikkor lens

Sorry but I just can't help myself when I see some stupendous piece of kit like this.

From Espikes09.blogspot.com:

First introduced in 1970 at the Photokina trade show in Cologne, Germany, the Fisheye-Nikkor 6mm f/2.8 lens offers an angle of view of 220º, making it — at the time — the world's most extreme wide-angle lens to cover an image area of 24 x 36 mm.

Lens production started in March 1972 and was only made available by special order, said Gray Levett, a co-founder of Grays of Westminster in London.

He and Tony Hurst spent six months on the trail of this lens and finally located it overseas.

"We were fortunate in securing it and it is now [April 2012] on sale for £100,000."

The lens is in mint condition.

It uses 12 glass elements in nine groups and weighs 5.2 kg.

It has a minimum focusing distance of 25 cm and features a slip-on front lens cap and is delivered in a rugged metal case.