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US 6,266,189 B1Granted
Zoom lens system having an image blur compensating function
AssigneeMinolta Co., Ltd.
InventorsKenji Konno, Kohtaro Hayashi
Life of this patent
Estimating the term…
Abstract
A zoom lens system has the first to fifth lens units from the object side. Refractive powers of the first to fifth lens units are positive, negative, negative, positive, negative, respectively. During zooming, the distances between the lens units are varied. Image blur compensation is made by parallel decentering the second lens unit. The second lens unit includes a first lens unit and a rear lens unit, either of which can be moved vertically to the optical axis to compensate for image blur. The distance between the front and rear lens units is fixed during a zooming mode.
Claims23
A zoom lens system comprising from an object side:
- a first lens unit having a positive refractive power, said first lens unit being moved toward the object side during zooming from a wide-angle limit to a telephoto limit;
- a second lens unit having a negative refractive power;
- a third lens unit having a positive refractive power;
- and
- a fourth lens unit having a positive refractive power, said fourth lens unit being moved toward the object side during zooming from the wide-angle limit to the telephoto limit,
- wherein one image blur compensating single lens element in any of the second to fourth lens units is moved vertically to an optical axis to compensate for an image blur, and wherein the following condition is fulfilled:
- 0.75<|fR/fW|<1.8
- where fR is a composite focal length of the third lens unit and the entire lens units provided at an image side of the third lens unit at the wide-angle limit, and fW is a focal length of the entire zoom lens system at the wide-angle limit.
5 more elements
A zoom lens system comprising from an object side:
- a first lens unit having a positive refractive power, said first lens unit being moved toward the object side during zooming from a wide-angle limit to a telephoto limit;
- a second lens unit having a negative refractive power;
- a third lens unit having a positive refractive power;
- and
- a fourth lens unit having a positive refractive power,
- wherein any of the second lens unit and lens units disposed on an image side of the second lens unit comprises from the object side a front lens and a rear lens unit, either said front lens unit or said rear lens unit being moved vertically to an optical axis to compensate for an image blur, wherein a distance between said front and rear lens units is fixed during zooming, wherein the following condition is fulfilled:
- 2.1<f1/fW<4.3
- where f1 is a focal length of the first lens unit, and fW is a focal length of the entire zoom lens system at the wide-angle limit.
5 more elements
A zoom lens system comprising from an object side:
- a first lens unit having a positive refractive power, said first lens unit being moved toward the object side during zooming from a wide-angle limit to a telephoto limit;
- a second lens unit having a negative refractive power;
- a third lens unit having a positive refractive power;
- and
- a fourth lens unit,
- wherein any of the second lens unit and lens units disposed on an image side of the second lens unit comprises, from the object side, a front lens unit and a rear lens unit, either said front or said rear lens unit being moved vertically from an optical axis to compensate for an image blur, wherein the following condition is fulfilled:
- 2.1<f1/fW<4.3
- where F1 is a focal length of the first lens unit, and fW is a focal length of the entire zoom lens system at the wide-angle limit.
5 more elements
A zoom lens system comprising from an object side:
- a first lens unit having a positive refractive power, said first lens unit being moved toward the object side during zooming from a wide-angle limit to a telephoto limit;
- a second lens unit having a negative refractive power, said second lens unit comprising from the object side a front lens unit and a rear lens unit, either said front lens unit or said rear lens unit being moved vertically to an optical axis to compensate for an image blur, a distance between said front and rear lens units being fixed during zooming and the front or the rear lens unit which is moved vertically to the optical axis to compensate for image blur has at least one positive lens element and at least one negative lens element;
- a third lens unit having a positive refractive power;
- and
- a fourth lens unit having a negative refractive power, wherein the following condition is fulfilled:
- 0.4<MT/MW<2.5
- wherein MT is a blur compensation movement amount of the second lens unit at the telephoto limit, and MW is a blur compensation movement amount of the second lens unit at the wide-angle limit.
4 more elements
Dependencies are inferred from the claim text.