| 摘要 |
PURPOSE: A fisheye lens is provided to obtain an angle of view over 180 degrees and high resolution and to reduce the number of lens elements. CONSTITUTION: A first lens element(E1) is a negative meniscus lens element. A convex surface of the first lens element faces an object. A second lens element(E2) and a third lens element(E3) form a doublet lens. The second lens element is a biconvex lens element. The third lens element is a biconcave lens element. A fourth lens element(E4) has a positive refractive power. An iris diaphragm(S) is located between the fourth lens element and a fifth lens element(E5). The fifth lens element and a sixth lens element(E6) form the doublet lens. The fifth lens element is a biconvex lens element. The sixth lens element is a negative meniscus lens element. The convex surface of the sixth lens element faces a focus. A seventh lens element(E7) has a positive refractive power. |
