US 5,502,594 A · Zoom lens incorporating vibration-proofing function

Abstract

A zoom lens incorporating a vibration-proofing function comprises, sequentially from an object side, a first lens group G.sub.1 having a positive refracting power; a second lens group G.sub.2 having a negative refracting power; a third lens group G.sub.3 having a negative refracting power; a fourth lens group G.sub.4 having a positive refracting power; and a fifth lens group G.sub.5 having a negative refracting power. The lens groups move so that when varying a magnifying power from a wide-angle end to a telephoto end, a spacing between the first and second lens groups G.sub.1, G.sub.2 increases; a spacing between the second and third lens groups G.sub.2, G.sub.3 changes linearly or non-linearly; and a spacing between the fourth and fifth lens groups G.sub.4, G.sub.5 is reduced. The zoom lens comprises a shift means for moving one of the third and fourth lens groups G.sub.3, G.sub.4 perpendicularly across the optical axis.

Claims20

Dependent claims

A zoom lens incorporating a vibration-proofing function, comprising, sequentially from an object side:

a first lens group having a positive refracting power;
a second lens group having a negative refracting power;
a third lens group having a negative refracting power;
a fourth lens group having a positive refracting power;
a fifth lens group having a negative refracting power, said lens groups moving so that when varying a magnifying power from a wide-angle end to a telephoto end, a spacing between said first and second lens groups increases;
a spacing between said second and third lens groups changes linearly or non-linearly;
and a spacing between said fourth and fifth lens groups is reduced and
a shift means for preventing image vibrations by moving one of said third and fourth lens groups in a direction transverse to the optical axis.

5 more elements

A zoom lens incorporating a vibration-proofing function, comprising, sequentially from an object side:

a first lens group having a positive refracting power;
a second lens group having a negative refracting power;
a third lens group having a negative refracting power;
a fourth lens group having a positive refracting power;
a fifth lens group having a negative refracting power, said lens groups moving so that when varying a magnifying power from a wide-angle end to a telephoto end, a spacing between said first and second lens groups increases;
a spacing between said second and third lens groups changes linearly or non-linearly;
and a spacing between said fourth and fifth lens groups is reduced;
and
a shift means for preventing image vibrations by moving said third lens group in a direction transverse to the optical axis, said zoom lens satisfying the following conditions:
0. 3<f.sub.1 /(f.sub.W .multidot.f.sub.T).sup.1/2 <1.5 (1)
0.3<f.sub.2 /f.sub.3 <5 (2)
0.8<.vertline.f.sub.3 .vertline./f.sub.W <2 (3)
where f.sub.1 is the focal length of said first lens group, f.sub.2 is the focal length of said second lens group, f.sub.3 is the focal length of said third lens group, f.sub.W is the focal length of a whole system at the wide-angle end, and f.sub.T is the focal length of the whole system at the telephoto end.

10 more elements

A zoom lens incorporating a vibration-proofing function, comprising, sequentially from an object side:

a first lens group having a positive refracting power;
a second lens group having a negative refracting power;
a third lens group having a negative refracting power;
a fourth lens group having a positive refracting power;
a fifth lens group having a negative refracting power, said lens groups moving so that when varying a magnifying power from a wide-angle end to a telephoto end, a spacing between said first and second lens groups increases;
a spacing between said second and third lens groups changes linearly or non-linearly;
and a spacing between said fourth and fifth lens groups is reduced;
and
a shift means for preventing image vibrations by moving said fourth lens group in a direction transverse to the optical axis, said zoom lens satisfying the following conditions:
0. 3<f.sub.1 /(f.sub.W .multidot.f.sub.T).sup.1/2 <1.5 (1)
0.25<D.sub.W3-4 /f.sub.W <0.8 (9)
0.6<f.sub.4 /.vertline.f.sub.5 .vertline.<1.2 (10)
where f.sub.1 is the focal length of said first lens group, f.sub.4 is the focal length of said fourth lens group, f.sub.5 is the focal length of said fifth lens group, f.sub.W is the focal length of a whole system at the wide-angle end, f.sub.T is the focal length of the whole system at the telephoto end, and D.sub.W3-4 is the spacing between said third and fourth lens groups at the wide-angle end.

10 more elements

Dependencies are inferred from the claim text.

Zoom lens incorporating vibration-proofing function

Life of this patent

Zoom lens incorporating vibration-proofing function

Life of this patent

Abstract

Claims20