| 摘要 |
<p>A photographic lens (10) consists of a first positive lens (11) and a second positive lens (12). The first lens (11) is a meniscus lens having a convex object side surface. The second lens (12) is a double-convex lens. Both an image side surface of the first positive lens (11) and an image side surface of the second positive lens (12) are formed to be aspherical. The photographic lens (10) satisfies the following conditions: <DF>5.6 ≤ f < 8; F1 > F2; 0.39 < F/F1 ≤ 0.5; 0.15 < R1/F < 0.19; 1.4 < (F/R3).f ≤ 3.0; and R3 > ¾R4¾ </DF> wherein F is an overall focal length of the photographic lens (10), F1 is a focal length of said first lens element (11), F2 is a focal length of said second lens element (12), f is a ratio of the overall focal length F to an effective aperture size that is defined by the first stop (14), R1 is a radius of curvature of the object side surface of said first lens element (11), and R3 and R4 are radii of curvature of the object side spherical surface and of an average spherical surface of the image side aspherical surface of the second lens element (12) respectively. <IMAGE></p> |
