| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To overcome a difficulty in realizing a compact zoom lens with a small lens diameter and a shorter optical system in entire length while obtaining a high variable power ratio and, an imaging apparatus using the same. <P>SOLUTION: A zoom lens comprises, in order from an object side: a first lens group being positive; a second lens group being negative; a third lens group being positive; a fourth lens group being negative; and a fifth lens group being positive. When varying power from a wide angle end to a telephoto end, the first lens group moves to the object side, the third lens group moves to the object side, and the fourth lens group moves to the object side, so that a distance between the first lens group and the second lens group increments, a distance between the second lens group and the third lens group decrements, a distance between the third lens group and the fourth lens group changes, and a distance between the fourth lens group and the fifth lens group increments, to satisfy the following conditional expressions(1) to (4): 1.0<β<SB POS="POST">4T</SB>/β<SB POS="POST">4w</SB><3.0 ...(1); 1.0<β<SB POS="POST">3T</SB>/β<SB POS="POST">3w</SB><5.0 ...(2); 1.0<β<SB POS="POST">5T</SB>/β<SB POS="POST">5w</SB><3.0 ...(3); and 0.05<¾f<SB POS="POST">4</SB>¾/f<SB POS="POST">t</SB><0.12 ...(4). <P>COPYRIGHT: (C)2013,JPO&INPIT</p> |
