An object of the present invention is to provide a fisheye lens, in spite
of its compactness, having an angle of view of 180 degrees and a fast
f-number of 2.8 with securing sufficient back focal length and suitable
for a digital camera. The fisheye lens consists of a front lens group G1
having negative refractive power and a rear lens group G2 having positive
refractive power locating with a space along the optical axis apart from
the front lens group G1. The front lens group G1 includes a plurality of
negative lens components, L1 and L2. The rear lens group G2 includes at
least one cemented lens L5, and given conditional expressions are
satisfied.