Zoom lens having weak front lens group
First Claim
1. A zoom lens comprising two groups of lens components including, from an object side, a first positive group and a second negative group and which zoom lens achieves zooming between a wide angle position and a narrow angle position by changing the distance between the first and the second groups,said first group including two lens units, a first, weak positive power unit having no strong lens component, said weak first unit positioned on an object side of said first group and a second positive unit following said first unit,said second group having negative power and providing most of the magnification change during zooming,said zoom lens satisfying the following conditions:
- ##EQU2## where K1 is the power of the first unit, Kw is the power of the zoom lens at its wide angle position, and Kt is the power of the zoom lens in its telephoto position.
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Accused Products
Abstract
A zoom lens having two groups of lens components including from the object side a positive group and a negative group. The positive group includes two lens units, a weak unit, and a positive unit, while the negative group has at least one negative lens component and provides most of the magnification change during zooming.
92 Citations
14 Claims
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1. A zoom lens comprising two groups of lens components including, from an object side, a first positive group and a second negative group and which zoom lens achieves zooming between a wide angle position and a narrow angle position by changing the distance between the first and the second groups,
said first group including two lens units, a first, weak positive power unit having no strong lens component, said weak first unit positioned on an object side of said first group and a second positive unit following said first unit, said second group having negative power and providing most of the magnification change during zooming, said zoom lens satisfying the following conditions: - ##EQU2## where K1 is the power of the first unit, Kw is the power of the zoom lens at its wide angle position, and Kt is the power of the zoom lens in its telephoto position.
- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A zoom lens comprising two groups of lens components including, from an object side, a first positive group and a second negative group and which zoom lens achieves zooming between a wide angle position and a narrow angle position by changing the distance between the first and the second groups,
said first group including two lens units and an aperture stop, a first, weak positive power unit having no strong lens component, said first unit having at least one aspheric surface, said first unit positioned on an object side of said first group and a second positive unit following said first unit, said aperture stop is positioned toward the object from said second unit, said second group having negative power and providing most of the magnification change during zooming, said zoom lens satisfying the following conditions: - ##EQU3## where K1 is the power of the first unit, Kw is the power of the zoom lens at its wide angle position, and Kt is the power of the zoom lens in its telephoto position.
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14. A zoom lens comprising two groups of lens components including, from an object side, a first positive group and a second negative group and which zoom lens achieves zooming between a wide angle position and a narrow angle position by changing the distance between the first and the second groups,
said first group including two lens units, a first, weak positive power unit having no strong lens component, said weak positive power first unit positioned on an object side of said first group and a second positive unit following said first unit, said second group having negative power and providing most of the magnification change during zooming, said zoom lens satisfying the following conditions: - ##EQU4## where K1 is the power of the first unit, Kw is the power of the zoom lens at its wide angle position, and Kt is the power of the zoom lens in its telephoto position, wherein the space between said first unit and said second unit varies during zooming.
Specification
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- Resources
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Current AssigneeEastman Kodak Company
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Original AssigneeEastman Kodak Company
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InventorsBetensky, Ellis I., Kreitzer, Melvyn H.
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Primary Examiner(s)Nguyen, Thong Q.
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Application NumberUS08/148,811Time in Patent Office834 DaysField of Search359/676-677, 359/691-693, 359/708, 359/717, 359/718, 359/728, 359/793-795US Class Current359/692CPC Class CodesG02B 15/16 with interdependent non-lin...
