| 摘要 |
A zoom lens and an image-pickup device are provided to properly shift an image at the high magnification ratio while making the diameter of the lens small. A zoom lens(1) comprises a first lens group(G1) having the positive refractive force, a second lens group(G2) having the negative refractive force, a third lens group(G3) having the positive refractive force, a fourth lens group(G4) having the positive refractive force, and a fifth lens group(G5). The first, second, third, fourth, and fifth lens groups are aligned from an object in order. If the position of the lens is changed from a wide view angle stage to a telescopic view angle stage, the first, second, third, and fourth lens groups move toward an optical axis. The second lens group moves toward an image side to increase a gap between the first and second lens groups and decrease a gap between the second and third lens groups. The third lens group moves toward the object, and the fourth lens group moves in a direction of the optical axis to compensate the position change of an image surface(IMG) accompanied with the movement of each lens group. The fifth lens group comprises a negative partial group(L51) having the negative refractive force and a positive partial group(L52) with the negative refractive force disposed at the upper side of the negative partial group while keeping an air space. An image is shifted by shifting the positive partial group in a vertical direction to the optical axis. An aperture iris is disposed at the fifth lens group while facing the object.
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