| 摘要 |
A fisheye lens, comprising a front group made up of a total of three groups, which are two concave lenses 1 and 2 whose concave surfaces are directed toward the image side, and a compound lens 3 whose concave surface is directed toward the image side and which has an overall convex or concave refractive power; and a rear group formed by three groups of convex lenses 4, 5 , and 6 , wherein the front group includes at least one compound lens set, the rear group includes one compound lens set, and at least a first surface of a first concave lens 1 of the front group is an aspheric surface, and satisfies specific conditions. As a result, it is possible to obtain a fisheye lens that can realize a foveal optical system with undiminished illuminance all the way to the periphery and with high resolution over the entire field of view, and with which a wide field of view and an extremely compact size can be attained with a single wide-angle optical system.
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