From Longman Dictionary of Contemporary Englishfish-eye lensˌfish-eye ˈlens noun [countable] TCPa type of curved lens (=piece of glass on the front of a camera) that allows you to take photographs of a wide area
Examples from the Corpus
fish-eye lens• Landscapes are treated unusually, in frescoes and also in sealstones, as if seen from the air or through a fish-eye lens.• The slopes were gentle and convex like the outer optic of a huge fish-eye lens.• Left: Even squeezed by the fish-eye lens the tank is impressive. 