Fisheye lens
Photopedia
18 October 2007 15:53
Despite the strange name, fisheye lenses are simply ultra wide-angle lenses that distort the image. This means that any straight lines at the edge of the image are curved outwards. At their most extreme these lenses give a circular image, rather than covering the whole frame.
Fisheyes are great for special effects and for producing dramatic shots, although if you get carried away you can soon find the novelty of the effect wears off!