Zoom lens, image pickup apparatus and digital equipment
AssigneeKonica Minolta Opto, Inc.
InventorYoshihito Souma
Life of this patent
Estimating the term…
Abstract
A zoom lens includes, in order from an object side thereof: a first lens group having a negative optical power and comprising a reflection optical element; a second lens group having a positive optical power; a third lens group having a negative optical power; a fourth lens group having a positive optical power; and, a fifth lens group. The first lens group and the fourth lens group are positioned at a fixed distance and at least the second lens group, the third lens group and the fifth lens group move along an optical axis, for varying a power of the zoom lens from a wide-angle end to a telephoto end. The zoom lens satisfies a predetermined expression relating to a focal length of the first lens group, and a focal length of the zoom lens at the wide-angle end.
Claims14
A zoom lens comprising, in order from an object side thereof:
- a first lens group having a negative optical power and comprising a reflection optical element for bending an optical path by almost 90 degrees;
- a second lens group having a positive optical power;
- a third lens group having a negative optical power;
- a fourth lens group having a positive optical power;
- and, a fifth lens group, wherein the first lens group and the fourth lens group are positioned at a fixed distance in a direction of the optical axis from an image plane of the zoom lens for varying a power of the zoom lens from a wide-angle end to a telephoto end, at least the second lens group, the third lens group and the fifth lens group move along an optical axis thereof for varying a power of the zoom lens from a wide-angle end to a telephoto end so as to reduce a distance between the first lens group and the second lens group and to reduce a distance between the third lens group and the fourth lens group and to change a distance between the fourth lens group and the fifth lens group, and the zoom lens satisfies a following expression:
- 1.0 <|fl|/fw <6.0, where f1 is a focal length of the first lens group, and fw is a focal length of the zoom lens at the wide-angle end.
Dependencies are inferred from the claim text.