| 摘要 |
PROBLEM TO BE SOLVED: To provide a low-cost and compact superwide-angle lens having a proper optical performance and a wide angle of view, such as about 170°as a photographing lens system for a solid state imaging element with an eight-piece spherical lens structure. SOLUTION: This superwide-angle lens includes a negative front group (GrF), an aperture diaphragm (ST), and a positive rear group (GrR) sequentially from an article side. The front group (GrF) has three negative lenses (L1-L3), and a positive lens (L4) sequentially directed at a concave surface from the article side toward an image side. The rear group (GrR) has a single positive lens (L8) at the nearest side to the image. Further, conditional formulae: -0.24<f/fF<-0.05, and 0.17<f/fR<0.42, wherein f is a focal length of the entire system, fF is a focal length of the front group (GrF), and fR is a focal length of the rear group (GrR), are satisfied. COPYRIGHT: (C)2004,JPO
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