Konica Minolta Photo Imaging, Inc.

Hiromichi Nose

Atsuo Masui

Mamoru Terada

Hiroyuki Matsumoto

A reduction optical system for forming, without re-imaging, a reduced image of a subject image formed by a main lens system. The reduction optical system has on the most object side a meniscus single-lens element convex to the object side, allowing for a high-performance, and compact reduction optical system by permitting lens replacement of the main lens system.

Reduction optical system with a meniscus single-lens element

A variable magnification optical system for forming an optical image of an object on the light receiving surface of the image sensor so that the magnification is variable includes from the object side: a first lens unit GRhaving negative optical power; a second lens unit GRhaving positive optical power; a third lens unit GRhaving positive optical power; and a fourth lens unit GRhaving positive or negative optical power. In magnification variation from the wide-angle end (W) to the telephoto end (T), at least first lens unit GRand the second lens unit GRare movable, and the fourth lens unit GRis stationary. An optical member having a wavelength selecting property is included in the fourth lens unit GR

Variable magnification optical system

An image forming device is provided with: a zoom lens system TL that performs magnification varying by changing the distance between the lens units; and an image sensor SR that converts an optical image formed by the zoom lens system TL into an electric signal. The zoom lens system TL comprises three lens units of negative, positive, positive configuration. The second lens unit Grcomprises three single lens elements of, from the object side, a positive lens element L, a negative meniscus lens element Lconvex to the object side and a positive lens element L. A condition 1.0&#x3c;|P22/P21|&#x3c;2.0 (P21 is the optical power of the object side positive lens element Lin the second lens unit GR, and P22 is the optical power of the negative meniscus lens element Lin the second lens unit GR) is satisfied.

Image forming device

An image forming device is provided with: a zoom lens system TL that performs magnification varying by changing the distance between the lens units; and an image sensor SR that converts an optical image formed by the zoom lens system TL into an electric signal. The zoom lens system TL includes at least a negative first lens unit GRand a positive second lens unit GR, and at least the first lens unit GRand the second lens unit GRmove in zooming from the wide angle end (W) to the telephoto end (T). The second lens unit GRincludes three lens elements of, from the object side, a positive meniscus lens element Lconvex to the object side, a negative lens element Land a positive lens element L, and the following condition is satisfied:&#x2212;1.0&#x3c;()/()&#x3c;0.0(CRis the front radius of curvature of the most object side lens element Lin the second lens unit GR, and CRis the rear radius of curvature of the most object side lens element Lin the second lens unit GR).

A zoom lens system for forming an optical image of a subject on the image-sensing surface of an image sensor has three lens units, namely, from the object side thereof, a first lens unit having a negative optical power, a second lens unit having a positive optical power, and a third lens unit having a positive optical power. The lens units each include at least one plastic lens element. The zoom lens system as a whole includes at least one glass lens element that fulfills a prescribed conditional formula.

Image-taking apparatus

A zoom lens system for forming an optical image of a subject on the image-sensing surface of an image sensor includes at least, from the object side thereof, a first lens unit having a negative optical power and a second lens unit having a positive optical power, and achieves zooming by varying the distances between the individual lens units in such a way that, during zooming from the wide-angle end to the telephoto end, the distance between the first and second lens units decreases. The first lens unit consists of two plastic lens elements.

A zoom lens system for forming an optical image of a subject on the image-sensing surface of an image sensor has three lens units, namely, from the object side thereof, a first lens unit having a negative optical power, a second lens unit having a positive optical power, and a third lens unit having a positive optical power, and achieves zooming by varying the distances between the individual lens units in such a way that, during zooming from the wide-angle end to the telephoto end, the distance between the first and second lens units decreases. The first lens unit is composed of two or more lens elements, and the first lens element, i.e., the lens element disposed at the object-side end of the first lens unit, and the last lens element, i.e., the lens element disposed at the image-side end of the third lens unit, are plastic lens elements. Moreover, a prescribed conditional formula is fulfilled.

A zoom lens system for forming an optical image of a subject on the image-sensing surface of an image sensor has three lens units, namely, from the object side thereof, a first lens unit having a negative optical power, a second lens unit having a positive optical power, and a third lens unit having a positive optical power, and achieves zooming by varying the distances between the individual lens units in such a way that, during zooming from the wide-angle end to the telephoto end, the distance between the first and second lens units decreases. The first lens unit is composed of two or more lens elements, and the first lens element, i.e., the lens element disposed at the object-side end of the first lens unit, is a plastic lens element. Moreover, a prescribed conditional formula is fulfilled.

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Toyokawa, Japan

Hiromichi Nose