Zoom lens and imaging apparatus including the same
AssigneeCanon Kabushiki Kaisha
InventorNobuyuki Miyazawa
Life of this patent
Estimating the term…
Abstract
At least one exemplary embodiment is directed to a zoom lens which includes a first lens group, which can have a positive refracting power; a second lens group, which can have a negative refracting power, and can move during zooming; a third lens group, which can have a positive refracting power; and a fourth lens group, which can have a positive refracting power, and can move during zooming, the lens groups being aligned in order from front to back, where the focal lengths fw and ft of the whole system at a wide-angle end and at a telescopic end, respectively, can satisfy the following conditions: 0.15<fw/f4 <0.26 1.0<f3/(fw·ft)1/2<1.2.
Claims9
A zoom lens comprising:
- a first lens group having a positive refracting power;
- a second lens group having a negative refracting power and moving during zooming;
- a third lens group having a positive refracting power;
- and
- a fourth lens group having a positive refracting power and moving during zooming, the lens groups being aligned in order from front side to rear side, wherein
- the third lens group comprises two or more positive lenses and a negative meniscus lens having a convex surface facing the front side;
- the fourth lens group comprises a positive lens and a negative lens;
- and
- the focal lengths f3 and f4 of the third lens group and the fourth lens group respectively, and the focal lengths fw and ft of the zoom lens system at a wide-angle end and at a telephoto end, respectively, satisfy the following conditions:
- 0.15<fw/f4 <0.26
- 1.0<f3/(fw·ft)1/2<1.2.
An imaging apparatus comprising:
- a solid-state image-pickup device;
- and
- a zoom lens for forming an image of an object on the solid-state image-pickup device,
- wherein the zoom lens includes:
- a first lens group having a positive refracting power;
- a second lens group having a negative refracting power and moving during zooming;
- a third lens group having a positive refracting power;
- and
- a fourth lens group having a positive refracting power and moving during zooming, the lens groups being aligned in order from an object side to an image-pickup side, wherein
- the third lens group comprises two or more positive lenses and a negative meniscus lens having a convex surface facing to the object side;
- the fourth lens group comprises a positive lens and a negative lens;
- and
- the focal lengths f3 and f4 of the third lens group and the fourth lens group, respectively, and the focal lengths fw and ft of the whole system at a wide-angle end and at a telephoto end, respectively, satisfy the following conditions:
- 0.15<fw/f4<0.26
- 1.0<f3/(fw·ft)1/2<1.2.
Dependencies are inferred from the claim text.