| 摘要 |
PROBLEM TO BE SOLVED: To provide a compact zoom lens that has a high variable power ratio and can obtain a high optical performance. SOLUTION: The zoom lens includes: a first lens group L1 having a positive refractive power; a second lens group L2 having a negative refractive power; a third lens group L3 having a positive refractive power; and a fourth lens group L4 having a positive refractive power. A stop SP is disposed between the second lens group L2 and the third lens group L3. The first lens group L1 has: a negative lens 1; a positive lens 2; and two positive lenses 3 and 4, each having a convex surface on an object side. The second lens group L2 has: at least three negative lenses 5, 6, and 8; and a positive lens 7. The third lens group L3 includes: a positive lens 9 having a convex surface on the object side; and a negative meniscus lens 10 having a concave surface on an image surface side. The zoom lens satisfies the following equations: 1.4<¾f<SB>2</SB>¾/f<SB>W</SB><2.0; and 0.3<f<SB>1</SB>/f<SB>T</SB><0.6; wherein a combined focal length of the first lens group L1 is f<SB>1</SB>, a combined focal length of the second lens group L2 is f<SB>2</SB>, a focal length of the entire system at a wide angle end is f<SB>W</SB>, and a focal length of the entire system at a telephoto end is f<SB>T</SB>. COPYRIGHT: (C)2011,JPO&INPIT |
