| 摘要 |
PURPOSE:To correct the spherical aberration, the coma, and the chromatic aberration of a titled lens well, by constituting a variator part with two convex single lenses, where strong concaves face to each other, and a compound lens between a biconvex lens and a biconcave lens and satisfying specific conditions. CONSTITUTION:The variator part of a zoom lens system consists of a concave lens whose strong concave is directed to the image side, a concave lens whose strong concave is directed to the object side, and a compound lens between a biconvex lens and a biconcave lens which are arranged in order from the object side, and conditional expression (1) is satisfied when the focal length of the variator and the focal length of the compound lens are denoted as f2 and fa respectively. Thus, the absolute value of the focal length fa is larger than that of the focal length f2 to lower the refracting power of the compound lens of the variator part, and the spherical aberration, the coma, and the chromatic aberration are corrected well without the influence upon the astigmatism and the distortion. |
