Olympus Optical Company, Ltd.

Olympus Corporation

Atsujiro Ishii

Shinichi Mihara

Toyoharu Hanzawa

Masahito Watanabe

Tetsuhide Takeyama

Hirokazu Konishi

Ayami Imamura

Yuji Miyauchi

Tsutomu Uzawa

Hironori Shibata

Masahiro Suzuki

Norihiko Aoki

Akira Mori

Naoki Fujii

Noriyuki Iyama

The invention relates to an electronic image pickup system whose depth dimension is extremely reduced, taking advantage of an optical system type that can overcome conditions imposed on the movement of a zooming movable lens group while high specifications and performance are kept. The electronic image pickup system comprises an optical path-bending zoom optical system comprising, in order from its object side, a 1-1st lens group G-comprising a negative lens group and a reflecting optical element P for bending an optical path, a 1-2nd lens group G-comprising one positive lens and a second lens group Ghaving positive refracting power. For zooming from the wide-angle end to the telephoto end, the second lens group Gmoves only toward the object side. The electronic image pickup system also comprises an electronic image pickup device I located on the image side of the zoom optical system.

Electronic image pickup system

The invention relates to an electronic image pickup system whose depth dimension is extremely reduced, taking advantage of an optical system type that can overcome conditions imposed on the movement of a zooming movable lens group while high specifications and performance are kept. The electronic image pickup system comprises an optical path-banding zoom optical system comprising, in order from its object side, a 1-1st lens group G-comprising a negative lens group and a reflecting optical element P for bending an optical path, a 1-2nd lens group G-comprising one positive lens and a second lens group Ghaving positive refracting power. For zooming from the wide-angle end to the telephoto end, the second lens group Gmoves only toward the object side. The electronic image pickup system also comprises an electronic image pickup device I located on the image side of the zoom optical system.

The invention relates to an electronic image pickup system whose depth dimension is extremely reduced, taking advantage of an optical system type that can overcome conditions imposed on the movement of a zooming movable lens group while high specifications and performance are kept. The electronic image pickup system comprises an optical path-bending zoom optical system comprising, in order from its object side, a-st lens group G-comprising a negative lens group and a reflecting optical element P for bending an optical path, a-nd lens group G-comprising one positive lens and a second lens group Ghaving positive refracting power. For zooming from the wide-angle end to the telephoto end, the second lens group Gmoves only toward the object side. The electronic image pickup system also comprises an electronic image pickup device I located on the image side of the zoom optical system.

The invention relates to an electronic image pickup system whose depth dimension is extremely reduced, taking advantage of an optical system type that can overcome conditions imposed on the movement, of a zooming movable lens group while high specifications and performance are kept. The electronic image pickup system comprises an optical path-bending zoom optical system comprising, in order from its object side, a 1-1st lens group G-comprising a negative lens group and a reflecting optical element P for bending an optical path, a 1-2nd lens group G-comprising one positive lens and a second lens group Ghaving positive refracting power. For zooming from the wide-angle end to the telephoto end, the second lens group Gmoves only toward the object side. The electronic image pickup system also comprises an electronic image pickup device I located on the image side of the zoom optical system.

The invention provides a zoom lens system that is reduced in terms of both size and cost. The zoom lens system comprises a first positive lens group G1, a second negative lens group G2, a stop S, a third positive lens group G3 and a fourth positive lens group G4. During zooming from a wide-angle end to a telephoto end of the system, while the first lens group G1 remains fixed, the second lens group G2 moves from an object side to an image plane side of the system, the third lens group G3 moves from the image plane side to the object side, and the fourth lens group G4 moves to keep an image plane at a constant position. The first lens group G1 is made up of a negative meniscus lens convex on an object side and a double-convex lens, the second lens group G2 is made up of a double-concave lens and a positive meniscus lens convex on an object side thereof, with an aspherical surface being used for a surface of the positive meniscus lens that is located on an image side thereof, the third lens group G3 is made up of a double-convex lens and a negative meniscus lens convex on an object side thereof, with an aspherical surface being used for a surface of the double-convex lens that is located on an object side thereof, and the fourth lens group G4 is made up of one double-convex lens.

Zoom lens system

A zoom lens comprises, in order from an object side to an image side, a lens group having negative refracting power, and a lens group having positive refracting power. Zooming is carried out with a change in a space between at least said two lens groups. The lens group having negative refracting power comprises a plurality of aspheric surfaces. The lens group having positive refracting power comprises at least one aspherie surface. The lens group having negative refracting power comprises at least three negative lenses, with satisfaction of the following condition: 2.3&#x3c;|f/f&#x3c;3.1, where fis a focal length of said lens group having negative refracting power, and fis a focal length of said lens group having positive refracting power.

Zoom lens

A zoom lens according to the present invention includes, in order from the object side, a first lens unit having a positive refractive power, a second lens unit having a negative refractive power, a third lens unit having a negative refractive power, and a fourth lens unit having a positive refractive power. During a magnification change from the wide-angle end through the telephoto end, the first lens unit and the fourth lens unit shift from the image-surface side toward the object side, a space between the first lens unit and the second lens unit increases, and spaces between individual lens units change. During a focusing from an object at the infinite distance onto an object at a near distance, the second lens unit and the third lens unit individually shift independently.

Zoom lens and apparatus using the same

A compact yet low-cost zoom lens system being particularly suited for use with small portable information terminal equipment is provided. The zoom lens system includes, in order from an object side thereof, a first, third and fourth lens groups G G and G that have positive refracting powers and a second lens group G that has negative refracting power. Lens group G remains fixed during zooming and lens groups G and G move during zooming and lens group G is movable during zooming. In one embodiment, the zoom lens system includes a negative lens located nearest to the imaging side of the second lens group G that satisfies condition (7).

A compact yet low-cost zoom lens system being particularly suited for use with small portable information terminal equipment is provided. The zoom lens system includes, in order from an object side thereof, first, third and fourth lens groups G,G,and G,respectively, that have positive refracting powers and a second lens group G,that has negative refracting power. Lens group G,remains fixed during zooming and lens groups G,and G,move during zooming and lens group G,is movable during zooming. the zoom lens system should satisfy condition (1) regarding the power of lens group G,condition (2) regarding the amount of movement of lens group G,during zooming condition (3) regarding the composite power of lens groups G,and G,and condition (10) regarding the actual value of the back focus.

A camera having an autofocus function, independent of a photographing optical system, includes a photographing optical system including synthetic resin lenses and an autofocus optical system, provided independent of the photographing optical system, having at least one synthetic resin lens and a stop decentered in a direction perpendicular to the optical axis of the synthetic resin lens. Thus, in the camera, the shift of the imaging position of the photographing optical system which is caused by an ambient temperature or humidity change is favorably corrected, and good photography can be performed.

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Hachioji, Japan

Atsujiro Ishii