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 24x36mm.
            Lens production started in March 1972, and was only made available to  special order, says Gray Levett, a co-founder of Gray's of Westminster.  He and Tony Hurst spend "six month on the trail of this lens and  finally located it overseas," he says. "We were fortunate in securing it  and it is now on sale for £100,000."
 The lens is in mint condition. It uses 12 glass elements in nine  groups and weighs 5.2kg. It has a minimum focussing distance of 25cm and  features a slip-on front lens cap and is delivered in a rugged metal  case.