| 摘要 |
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 G 1 having negative refractive power and a rear lens group G 2 having positive refractive power locating with a space along the optical axis apart from the front lens group G 1 . The front lens group G 1 includes a plurality of negative lens components, L 1 and L 2 . The rear lens group G 2 includes at least one cemented lens L 5 , and given conditional expressions are satisfied.
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