| 摘要 |
PROBLEM TO BE SOLVED: To provide an imaging lens which is wide-angle with a half view angle of approximately 32 to 33 degrees, is bright with an F number equivalent to approximately F2.5, is compact with a total length of approximately 2.3 times an image height, presents low variation of distortion aberration while focusing, and offers superior performance.SOLUTION: An imaging lens, comprising a first lens group Gr1 having positive refractive power, an aperture stop AD, and a second lens group Gr2 having positive refractive power arranged in order from the object side to the image side, constitutes an optical system for forming an optical image of an object. The first lens group Gr1 has at least two lenses while the second lens group Gr2 has at least four lenses, and the whole optical system comprises no more than seven lenses. Focus is shifted from the infinity side toward the proximity side by moving at least two lenses of at least four lenses of the second lens group Gr2 from the object side toward the image side as focusing lenses. |
