| 摘要 |
PROBLEM TO BE SOLVED: To achieve a resolution corresponding to a small imaging element of 10 million to 15 million pixels although a half field angle at a short focal end is ≥38°, a variable power ratio is ≥8 times, and the number of lens constitution is as few as around 10 pieces.SOLUTION: A zoom lens includes a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, a third lens group G3 having a positive refractive power, and a fourth lens G4 group having a positive refractive power, which are disposed in order from an object side to an image side and an aperture stop AD disposed between the second and third lens groups. When changing the magnification of the zoom lens from a short focal end to a long focal end, an interval between the first lens group G1 and the second lens groups G2 increases, an interval between the second lens group G2 and the third lens group G3 decreases, and an interval between the third lens group G3 and the fourth lens group G4 increases. The first lens group G1 and the third lens group G3 are moved so as to be positioned at an object side at the long focal end relative to positions at the short focal end. The third lens group G3 has a first positive lens L31, a second positive lens L32 and a negative lens L33, and the two positive lenses have abnormal dispersibility. |
