| 摘要 |
PROBLEM TO BE SOLVED: To provide an inner focus zoom lens which has a compact property by which a telephoto ratio is within 0.75 regardless of the high magnification zoom of about X5 zoom ratio, by which sufficient peripheral light quantity is secured without increasing a lens diameter and that has a high optical performance over the entire area of zooming or the entire area of an object distance. SOLUTION: This is a telephoto zoom lens that orderly possesses from an object side, a first lens group L1 having positive refracting power, a second group L2 having negative refracting power, a third group L3 having negative refracting power, a fourth group L4 having positive refracting power, a fifth group L5 that is a diaphragm, a sixth group L6 having positive refracting power and a seventh group L7 having negative refracting power, and variable power from a wide angle end to a telephoto end is executed by moving the first group, the second group, the fourth group, the fifth group and the sixth group to the object side, and image surface movement in accordance with the variable power is executed by moving the seventh group and focusing is executed by moving the second lens group to an image surface side, and possesses a negative lens and a positive meniscus lens whose convex surface is faced to the object side so as to reduce the fluctuation of a spherical aberration in accordance with the focusing on a telephoto side.
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