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US 5,499,141 AGranted
Zoom lens
AssigneeNikon Corporation
InventorMotoyuki Ohtake
Life of this patent
Estimating the term…
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AssigneeNikon Corporation
InventorMotoyuki Ohtake
Estimating the term…
The zoom lens of the present invention comprises, in the order from the 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 negative refractive power, a fourth lens group having a positive refractive power and a fifth lens group having a negative refractive power, in which, at a refractive power varying operation from the wide angle end to the telescopic end, at least the first and fifth lens groups move toward the object side, while the air gaps between the first and second lens groups and between the second and third lens groups increase and the air gap between the fourth and fifth lens groups decreases, and there is satisfied a condition: 0.4<.DELTA.Bf/(ft-fw)<0.8 wherein .DELTA.Bf is the amount of axial movement of the fifth lens group at the refractive power varying operation from the wide angle end to the telescopic end, and fw and ft are focal length of the entire lens system respectively at the wide angle end and at the telescopic end.
A zoom lens comprising, in the order from the 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 negative refractive power, a fourth lens group having a positive refractive power and a fifth lens group having a negative refractive power, in which, at a refractive power varying operation from the wide angle end to the telescopic end, at least said first and fifth lens groups move to the object side, the air gaps between said first and second lens groups and between said second and third lens groups increase while the air gap between said fourth and fifth lens groups decreases, wherein:
A zoom lens comprising, in the order from the 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 negative refractive power, a fourth lens group having a positive refractive power and a fifth lens group having a negative refractive power, in which, at a refractive power varying operation from the wide angle end to the telescopic end, at least said first and fifth lens groups move to the object side, the air gaps between said first and second lens groups and between said third and fourth lens groups increase while the air gap between said fourth and fifth lens groups decreases, wherein:
Dependencies are inferred from the claim text.