Zoom lens
AssigneesTamron Co., Ltd., Sony Corporation
InventorsDayong Li, Daisuke Kuroda, Takuya Kato
Life of this patent
Estimating the term…
Abstract
A zoom lens includes sequentially from an object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, a fourth lens group having a negative refractive power, a fifth lens group having a positive refractive power, and a sixth lens group having a negative refractive power. The zoom lens varies the interval between the lens groups to perform zooming; shifts the second lens group in a direction substantially orthogonal to the optical axis to correct image blur occurring with optical system vibrations; and satisfies given conditions, enabling a compact size and a high zoom ratio to be achieved while improving imaging performance.
Claims5
A zoom lens comprising sequentially from an object side:
- a first lens group having a positive refractive power;
- a second lens group having a negative refractive power;
- a third lens group having a positive refractive power;
- a fourth lens group;
- and
- at least one lens group subsequent to the fourth lens group toward an image plane, wherein
- zooming between a wide angle edge and a telephoto edge is performed by varying intervals between the lens groups, along a direction of an optical axis,
- correction of hand-shake occurring with optical system vibration is performed by shifting any one among the entire second lens group and a portion of lenses forming the second lens group, in a direction that is substantially orthogonal to the optical axis, and
- conditional expression (1) 0.5≦D2W×(−F2)/(Ft×tan(ωw))≦2.0 and condition expression (2) 90≦(F1×Ft)/(−F2×F3)≦200 are satisfied, where D2W is an interval between the second lens group and the third lens group at the wide angle edge, F1 is the focal length of the first lens group, F2 is the focal length of the second lens group, F3 is the focal length of the third lens group, Ft is the focal length of the optical system overall at the telephoto edge, and ωw is a half-angle at the wide angle edge.
Dependencies are inferred from the claim text.