| 摘要 |
The present invention relates to a fisheye lens having one to seven lens elements, of which a view angle is higher than 180 degrees, and calibration distortion is equal to or less than 7%. The first lens element is a negative meniscus lens element with a convex surface facing an object, and the second lens element is any one of a positive concave lens element and a flat concave lens element with a flat surface facing the object. The third lens element is any one of a positive convex lens element and a positive meniscus lens element with a convex surface facing the object, and an aperture is positioned between the third lens element and the fourth lens element. The first lens element has a refractive index of 1.8 or more, and an Abbe number of 20 to 50. The second lens element has a refractive index of 1.7 or more, and an Abbe number of 40 to 60. The third lens element has a refractive index of 1.8 or more, and an Abbe number of 30 or less. |
