CPC G02B 15/143507 (2019.08) [G02B 13/009 (2013.01); G02B 15/14 (2013.01); G02B 5/005 (2013.01); G02B 5/208 (2013.01); G02B 13/02 (2013.01); G02B 27/0025 (2013.01)] | 18 Claims |
1. A zoom optical system, comprising:
a first lens group comprising a negative refractive power;
a second lens group comprising a positive refractive power; and
a third lens group comprising a positive refractive power,
wherein
the first to third lens groups are sequentially disposed from an object side toward an imaging plane,
upon zooming from a wide-angle position to a telephoto position, a gap between the first and second lens groups is decreased,
a gap between the second and third lens groups is adjustable,
the first lens group comprises a first lens and a second lens having a convex object-side surface, the second lens group comprises a third lens, a fourth lens having a convex object-side surface, and a fifth lens, and the third group comprises a sixth lens, and
1.9≥|fG1/fw|≥3.0, 4.0<ft/fw<7.0, and 1.61<n4<1.68, where fw is an overall focal length of the zoom optical system in the wide-angle position, fG1 is a synthesized focal length of the first lens group, ft is an overall focal length of the zoom optical system in the telephoto position, and n4 is a refractive index of the fourth lens.
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