Hoya Corporation

Pentax Corporation

Asahi Kogaku Kogyo Kabushiki Kaisha

Hitachi, Ltd.

Masaru Eguchi

Tetsuya Nakamura

Koichi Furusawa

Ryo Ozawa

Tetsuya Utsui

Shinsuke Okada

Toshiki Nakamura

Tetsuya Abe

Takayuki Ito

Takaomi Sekiya

Koichiro Hayakawa

Hiroshi Kikuchi

Kazuyuki Takahashi

Akira Arimoto

Shinichi Arai

Yutaka Takakubo

Naomi Matsumoto

Yoshitake Tanno

Chihiro Mochizuki

An optical element including a glass body is provided. The optical element includes a colored layer provided inside the glass body and positioned outside an effective aperture of the optical element. Coloring of the colored layer is a reduction pigment occurring in a glass component of the glass body. The colored layer suppresses occurrence of stray light and obtains sufficient light-shielding properties, so that a superior image quality can be achieved.

Optical element and optical apparatus

A zoom lens system includes a negative first lens group, a positive second lens group, and a positive third lens group, in that order from the object side, wherein upon zooming from the short focal length extremity to the long focal length extremity, the distance between the first lens group and the second lens group decreases, and the distance between the second lens group and the third lens group increases. The second lens group includes a positive first sub-lens group and a negative second sub-lens group, in that order from the object side. The second sub-lens group is a focusing lens group which is moved along the optical axis direction during a focusing operation. The following condition (1) is satisfied:&#x2212;1.5&#x3c;2/2&#x3c;&#x2212;0.7&#x2003;&#x2003;(1),wherein F2 designates the focal length of the second lens group, and F2B designates the focal length of the second sub-lens group.

Zoom lens system

A high zoom-ratio zoom lens system includes a positive first lens group, a negative second lens group, a positive third lens group and a positive fourth lens group. Upon zooming, the distance between the first and second lens groups increases, the distance between the second and third lens groups decreases, and the distance between the third and fourth lens groups increases. The first lens group includes a negative lens element, and two positive lens elements. The absolute value of the radius-of-curvature of the image-side surface of the negative lens element within the first lens group is smaller than the absolute value of the radius-of-curvature of the object-side surface of the positive lens element on the object side within the first lens group. The following condition (1) is satisfied:1.95&#x3c;11&#x2003;&#x2003;(1),wherein n11 designates the refractive index at the d-line of the negative lens element within the first lens group.

High zoom-ratio zoom lens system and electronic imaging apparatus using the same

A zoom lens system includes a negative first lens group, positive second and third lens groups, wherein upon zooming from the short to the long focal length extremities, the distance between the first and second lens groups decreases and the distance between the second and third lens groups changes. The second lens group includes a biconvex positive lens element with an aspherical surface on each side, and a negative meniscus lens element with an aspherical surface, and a concave surface on the image side. The following condition (1) is satisfied:5&#x3c;22&#x3c;8&#x2003;&#x2003;(1),wherein m2t and m2w designate the lateral magnifications of the second lens group at the long and short focal length extremities, respectively, when focused on an object at infinity.

Zoom lens system and electronic imaging apparatus provided with the same

A zoom lens system includes a positive first lens group, a negative second lens group, a positive third lens group and a positive fourth lens group, in that order from the object side. Upon zooming from the short to long focal length extremities, the distance between the first and second lens groups increases, the distance between the second and third lens groups decreases, and the distance between the third and fourth lens groups changes. The second lens group includes a negative lens element having a concave surface on the image side, a negative lens element having a concave surface on the image side, and a plastic positive lens element having an aspherical surface on at least one side and having a convex surface on the object side, in that order from the object side.

A high zoom-ratio zoom lens system includes a positive first lens group, a negative second lens group, a positive third lens group and a positive fourth lens group, in that order from the object side. Upon zooming from the short focal length extremity to the long focal length extremity, at least the first through third lens groups move along the optical axis direction in a manner so that the distance between the first lens group and the second lens group increases, the distance between the second lens group and the third lens group decreases, and the distance between the third lens group and the fourth lens group increases, wherein the amount of movement of the first lens group during zooming is larger than that of the third lens group.

High zoom-ratio zoom lens system

A zoom lens system includes a negative first lens group, positive second and third lens groups, wherein upon zooming from the short to long focal length extremities, the distance between the first and second lens groups decreases and the distance between the second and third lens groups changes. The second lens group includes a biconvex positive lens element with an aspherical surface on each side, and a negative meniscus lens element with an aspherical surface, and a concave surface on the image side. Conditions (1) and (2) are satisfied:&#x3bd;&#x3e;80&#x2003;&#x2003;(1),and&#x3e;0.53&#x2003;&#x2003;(2),wherein &#x3bd;d designates the Abbe number at the d-line of the biconvex positive lens element within the second lens group, and Pg_F designates the partial dispersion ratio of the biconvex positive lens element within the second lens group.

A zoom lens system includes a negative first lens group, a positive second lens group, and a positive third lens group, in that order from the object side, wherein upon zooming from the short focal length extremity to the long focal length extremity, the distance between the first lens group and the second lens group decreases, and the distance between the second lens group and the third lens group increases. The second lens group includes a positive first sub-lens group and a negative second sub-lens group, in that order from the object side. The second sub-lens group is a negative single lens element serving as an image-stabilizer lens group which moves in directions orthogonal to the optical axis to change the imaging position to correct image shake.

A zoom lens system includes a negative first lens group, a positive second lens group, and a positive third lens group, in that order from the object side, wherein upon zooming from the short to long focal length extremities, the distance between the first lens group and the second lens group decreases, and the distance between the second lens group and the third lens group increases. The second lens group includes a positive first sub-lens group and a negative second sub-lens group, in that order from the object side. In at least part of the zooming range of the zoom lens system, the second sub-lens group and the third lens group each serves as a focusing lens group that is moved along the optical axis during a focusing operation.

A high zoom-ratio zoom lens system includes a positive first lens group, a negative second lens group, a positive third lens group, and a positive fourth lens group, in that order from the object side. Upon zooming from the short to long focal length extremities, at least the first through third lens groups are moved along the optical axis direction, wherein an amount of movement of the first lens group is greater than that of the third lens group. The following conditions (1), (2) and (3) are satisfied:0.9&#x3c;1&#x3c;2&#x2003;&#x2003;(1),3&#x3c;1/&#x3c;7&#x2003;&#x2003;(2), and&#x2212;8&#x3c;1/2&#x3c;&#x2212;5&#x2003;&#x2003;(3),wherein FT and FW designate the entire focal length of the zoom lens system at the long and short focal length extremities, respectively; and F1 and F2 designate the focal length of the first and second lens groups, respectively.

A zoom lens system includes a negative first lens group, a positive second lens group, and a positive third lens group, in this order from the object. Each of the negative first lens group, the positive second lens group and the positive third lens group moves along the optical axis upon zooming. The positive second lens group includes a positive first lens element, a negative second lens element, and a negative third lens element, in this order from the object. The zoom lens system satisfies the following conditions:2&#x3c;2/&#x3c;3&#x2003;&#x2003;(1)0.4&#x3c;2/3&#x3c;0.8&#x2003;&#x2003;(2)

Zoom lens system and electronic imaging apparatus that uses the same

A high zoom-ratio zoom lens system includes a positive first lens group, a negative second lens group, a positive third lens group, and a positive fourth lens group, in that order from the object side, wherein upon zooming from the short to the long focal length extremities, the first through fourth lens groups are moved along the optical axis direction, wherein an amount of movement of the first lens group is greater than that of the third lens group. The following conditions (1) and (2) are satisfied:1.4&#x3c;1&#x3c;2.4&#x2003;&#x2003;(1), and5&#x3c;22&#x3c;10&#x2003;&#x2003;(2),wherein FT designates the entire focal length at the long focal length extremity, F1 designates the focal length of the first lens group, and M2T and M2W designate the magnification of the second lens group with respect to an object at infinity at the long and short focal length extremities, respectively.

A zoom lens system includes a positive first lens group, a negative second lens group, a positive third lens group, and a positive fourth lens group, in this order from the object. Upon zooming from the short focal length extremity to the long focal length extremity, all of the first through fourth lens groups move along the optical axis. The zoom lens system satisfies the following condition: 3&#x3c;T1/F2&#x3c;4 . . . (1) wherein T1 designates the traveling distance of the first lens group upon zooming from the short focal length extremity to the long focal length extremity; and F2 designates the focal length of the second lens group.

A rear focus wide-angle lens system includes a first lens group, a diaphragm, and a second lens group, in this order from the object. The second lens group is moved along the optical axis of the lens system when focusing is performed from infinity to an object at a closer distance. The rear focus wide-angle lens system satisfies the condition 1.5 &#x3c;F/F&#x3c;3.0, wherein Fdesignates the focal length of the first lens group and Fdesignates the focal length of the second lens group.

Rear focus wide-angle lens system and electronic imaging device using the same

A focus adjustment method of a zoom lens system is provided for correcting a focal point shift caused by manufacturing error. The zoom lens system includes three movable lens groups in which at least two of said lens groups are moved to perform zooming to form an image onto an imaging device. In the zoom lens system, a finite number of focal length positions at which a focus adjustment is performed is provided. The lens group closest to the imaging device out of the three lens groups includes a focusing lens group. A position of the focusing lens group is controlled via pulses of a stepping motor. The focus adjustment method includes the combination of performing the above control of the focusing lens group to determine a position of the focusing lens group via pulses of the stepping motor and determining an amount of adjustment of the imaging device.

Growing community of inventors

Saitama, Japan

Masaru Eguchi