Tamron Company, Ltd.

Other

Sony Corporation

Nikon Corporation

Sumita Optical Glass, Inc.

Dayong Li

Toru Nara

Hiroshi Yamamoto

Yoshito Iwasawa

Takuya Kato

Daisuke Kuroda

Hiroki Watanabe

Hiroki Harada

Hisayuki Yamanaka

Akio Arakawa

Yuichi Muramatsu

Morito Kanke

Shotaro Sano

Jun Otake

A relay optical systemfor a rigid endoscope includes a lens fixing frameand a plurality of lenses. The lens fixing framehas a plurality of tubular bodies. The plurality of tubular bodiesare joined coaxially to each other. The plurality of lensesare located at positions other than a joint position jp of the tubular bodiesin an axis direction of the lens fixing frame. The plurality of lensesare located in the lens fixing frameso as to have a coincident optical axis. The plurality of lensesdo not include a cemented lens.

Relay optical system for rigid endoscope

An object of the present invention is to provide a low-cost, miniature, wide-angle high-zoom-ratio zoom lens that has high imaging performance, and an imaging apparatus equipped with the zoom lens. To achieve the object, a zoom lens including a first lens group having positive refracting power, a second lens group having negative refracting power and a third lens group having positive refracting power in order from an object side in which a lens group P having positive refracting power is arranged closer to an image plane side than the third lens group.

Zoom lens and imaging apparatus

A zoom lens includes sequentially from an object side, a first lens section Ghaving a negative refractive power and a second lens section Ghaving a positive refractive power. The first lens section Gincludes sequentially from the object side, a negative lens L, a negative lens L, and a positive lens L. Both surface of the negative lens Lare aspheric. The second lens section Gincludes sequentially from the object side, a front group Ghaving a positive refractive power and a rear group Ghaving a positive refractive power. Both surfaces of a negative lens Lincluded in the rear group Gare aspheric. The zoom lens can maintain high imaging performance while achieving size reductions and wide angle views by satisfying given conditions.

Zoom lens

A zoom lens includes sequentially from an 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 positive refractive power, a fourth lens group having a negative refractive power, a fifth lens group having a positive refractive power, and a sixth lens group having a negative refractive power. The zoom lens varies the interval between the lens groups to perform zooming; shifts the second lens group in a direction substantially orthogonal to the optical axis to correct image blur occurring with optical system vibrations; and satisfies given conditions, enabling a compact size and a high zoom ratio to be achieved while improving imaging performance.

Wide-angle large-aperture zoom lens provides a field angle greater than 75&#xb0; at the wide-angle end and a variable magnification power of 2.5 or greater, and can downsize a compensation mechanism for image blur due to hand tremors. The zoom lens includes a first lens group LGof positive refractive power, a second lens group LGof negative refractive power, a third lens group LGof positive refractive power, and a fourth lens group LGof positive refractive power, all arranged in sequence from the closest to an object to the closest to an imaging plane, and permits magnification power to vary by varying clearances between adjacent ones of the first lens group LGto the fourth lens group LG. Part of the lens pieces in the third lens group is moved orthogonally to the optical axis to compensate for image blur due to hand tremors.

Large-aperture zoom lens

A zoom lens includes, sequentially from an 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 positive refractive power; and a fourth lens group having a positive refractive power. Zoom is performed by moving the second and the third lens groups in a direction along an optical axis. The fourth lens group consists of, sequentially from the object side, a front group having a positive refractive power, an intermediate group configured by a cemented lens formed by a positive lens and a negative lens and having an overall refractive power that is negative, and a rear group having a positive refractive power. Blur is corrected by moving the intermediate group in a direction that is substantially orthogonal to the optical axis.

A zoom lens includes, sequentially from an object side, a first lens group having a positive refractive power; a second lens group having negative refractive power; a third lens group having a positive refractive power; and a fourth lens group having a positive refractive power. The third lens group includes, sequentially from the object side, a front group having a positive refractive power and a rear group having a negative refractive power. Zoom is performed by moving the second lens group and the third lens group in a direction along an optical axis, and by integrally moving the front group and the rear group in a direction along the optical axis. Focusing is preformed by moving the front group in a direction along the optical axis.

The present invention is a variable power zoom lens that is suitable to APS-format single-lens reflex cameras. The zoom lens has the foremost or first lens group Gof positive refractivity, the second lens group Gof negative refractivity, the third lens group Gof positive refractivity, and the fourth lens group Gof positive refractivity disposed in sequence from a position closer to the object to photograph toward the image plane. The third lens group Ghas a front lens subset GF of positive refractivity and a back lens subset GB, and the back lens subset GB alone is moved orthogonal to the optical axis to correct a blur of an image on the image plane caused by a shake of photographer's hands.

Variable power zoom lens

The present invention is directed to high magnification compact zoom lenses that are reduced in diameter of groups of lens pieces closer to the imaging plane to provide downsized lightweight zoom lenses of magnification as high as 20 diameters, with an image stabilizer or vibration compensating mechanism being also reduced in dimensions. An exemplary improved high magnification zoom lens has four groups of lens pieces, namely, the first or leading lens group Gof positive refractivity in the foremost position closer to the subject, the second lens group Gof negative refractivity, the third lens group Gof positive refractivity, and the fourth lens group Gof positive refractivity in the rearmost position closer to the imaging plane, all arranged in this order. In displacing the entire lens optics of the zoom lens from the wide-angle end to the telephoto end, the second lens group Gare moved toward the imaging plane and the fourth lens group Gare moved to compensate for a varied position of the resultant image while the first and third lens groups, Gand G, have their respective positions fixed along the optical axis. The zoom lens satisfies the requirements as defined in the following formulae: f/f&#x3e;2.0 and v&#x3e;65 where fis a focal length of the third lens group G, fis the focal length of the fourth lens group, vis an average of Abbe contrasts of all the convex lens pieces in the fourth lens group G

High magnification compact zoom lens

The present invention is a variable power zoom lens that is suitable to APS-format single-lens reflex cameras. The zoom lens has the foremost or first lens group Gof positive refractivity, the second lens group Gof negative refractivity, the third lens group Gof positive refractivity, and the fourth lens group Gof positive refractivity disposed in sequence from a position closer to the object toward the image plane, and it meets requirements as defined in conditional formulae as follows:6&#x3c;/()&#x3c;10where Lw is the entire length of the lens optics (i.e., from the front surface of the foremost lens piece to the image plane) at the wide-angle end, Ft is a focal length of the lens optics in whole at the telephoto end, and Fw is the focal length of the lens optics in whole at the wide-angle end.

The present invention is directed to wide-angle zoom lenses dedicated to single-lens reflex digital cameras, which attains zoom ratio greater than 2. Such a wide-angle zoom lens has four groups of lens pieces, namely comprising the leading or foremost 1st lens group of negative refractivity closest to an objective field, the succeeding 2nd lens group of positive refractivity, the third lens group of negative refractivity, and the trailing 4th lens group of positive refractivity arranged in this order to move each lens group to vary optical power; and the 1st lens group includes a front subset of the lens pieces of negative refractive power and a rear subset of negative refractive power. The front-end lens piece in the 1st lens group is shaped in negative meniscus lens that has its concave surface faced toward an imaging plane and has the opposite surfaces shaped aspherical. The front and rear subsets of the 1st lens group meet requirements of a focal length as expressed in the following formula:3.5&#x2266;|11where f1is a focal length of the front subset of the lens pieces in the 1st lens group and f1is the focal length of the rear subset in the 1st lens group.

Wide-angle zoom lens

A zoom lens includes, sequentially from an object side, a positive first lens group; a negative second lens group; a positive third lens group; and a positive fourth lens group, where 2.0&#x2266;D23W/FW&#x2266;3.0 is satisfied. D23W is an interval, at a wide angle edge, between a lens that among lenses of the second lens group, is farthest on an imaging plane side and a lens that among lenses of the third lens group, is farthest on the object side. FW is a focal length of an optical system of the zoom lens at infinity focus, at the wide angle edge.

The invention is directed to inner-focusing zoom lenses that include multi groups of lens pieces, namely, the first lens group or the leading lens group of positive refractivity, the second lens group of negative refractivity, and the remaining trailing groups of positive refractivity, as a whole. At least one group of positive refractivity among the trailing groups includes two or more negative lens pieces, at least one of which is connected on its surface to another lens piece to form a duplicated composite lens so that the junction between two of them functions to diverge incident beams. Assuming now that a sum of the refractivities of all the junctions of the composite lenses can be expressed as &#x3a3;&#x3c6;=&#x3a3;|(N1&#x2212;N2)/R| where N1 and N2 are refractivities that substances before and after the junction of the composite lenses respectively have, R is a radius of curvature of the junction, ft is a focal length of the comprehensive lens optics of the zoom lens at the telephoto end.

A zoom lens includes sequentially from an object side, a positive first lens group; a negative second lens group; a diaphragm; a positive third lens group; a positive fourth lens group; and a positive fifth lens group, wherein a first condition 0.8&#x2266;(SLM&#x2212;(SLW+SLT)/2)/FW&#x2266;2.0 and a second condition F14t&#x2266;0 are satisfied. SLW is a distance from the diaphragm at a wide angle edge to an imaging plane; SLM is a distance from the diaphragm at an intermediate zoom position to the imaging plane; SLT is a distance from the diaphragm at a telephoto edge to the imaging plane; FW is optical system focal length for infinity at the wide angle edge; and F14t is a combined focal length for the first to the fourth lens groups at the telephoto edge.

Growing community of inventors

Saitama, Japan

Dayong Li