In order to provide a large relative-aperture super wide-angle lens having the inclusive angle of 2 115 or more with the conventional projection method (yftan ) having the relative-aperture of about F 2.8, having compactness and high optical performance, and having small variation of aberration in relatively...http://www.google.com.au/patents/US6621645?utm_source=gb-gplus-sharePatent US6621645 - Super wide-angle lens and photographing apparatus having the same
