Olympus Corporation

Olympus Imaging Corporation

Takayuki Mimura

Kanato Adachi

Hisashi Goto

Takahiro Amanai

Masahiro Imamura

Keigo Matsuo

Yoshihiro Uchida

A zoom lens includes in order from an object side to an image 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 positive refractive power, and a fourth lens unit having a negative refractive power, and includes an aperture stop which is disposed between the second lens unit and the fourth lens unit, and the first lens unit includes a negative lens and a plurality of positive lenses, and at the time of zooming from a wide angle end to a telephoto end, a distance between the first lens unit and the second lens unit widens, a distance between the second lens unit and the third lens unit narrows, and a distance between the third lens unit and the fourth lens unit changes, and the zoom lens satisfies predetermined conditional expressions.

Zoom lens and image pickup apparatus using the same

Provided are a variable power optical system in which the value of the entire length with respect to the image height is reduced and the aberration is well corrected, and an image pickup device comprising the same. Specifically provided is a variable power optical system comprising, in order from the object side, at least a first lens group having negative refractive power, a variable power group having positive refractive power, and a final lens group having positive refractive power, wherein the variable power group is provided with, in order from the object side, a first lens element having positive refractive power, a second lens element, and a third lens element, the second lens element has a convex shape on the object side, and the final lens group comprises a positive lens, the variable power optical system satisfying the following conditional expression:10&#x2266;&#x2266;45&#x2212;1.0&#x3c;(22)/(22)&#x3c;1.0where VdLg is the Abbe number of the positive lens of the final lens group with respect to the d line, Ris the curvature radius of the object-side surface of the second lens element, and Ris the curvature radius of the image-side surface of the third lens element.

Variable power optical system and image pickup apparatus having the same

During zooming from the wide angle end to the telephoto end, the distance between the first lens unit having a positive refractive power and the second lens unit having a negative refractive power, the distance between the second lens unit and the third lens unit having a positive refractive power, and the distance between the third lens unit and the fourth lens unit having a negative refractive power vary. In zooming from the wide angle end to the telephoto end, the first lens unit is located closer to the object side at the telephoto end than at the wide angle end. The first lens unit consists of two lenses including a negative lens and a positive lens. The first lens unit has at least one aspheric surface in the optical path. The zoom lens satisfies the following conditional expression (1):0.5&#x3c;(/&#x3b2;)/&#x3c;1.0&#x2003;&#x2003;(1).

Provided are a variable power optical system in which the value of the entire length with respect to the image height is reduced and the aberration is well corrected, and an image pickup device comprising the same. Specifically provided is a variable power optical system comprising, in order from the object side, at least a first lens group having negative refractive power, a variable power group having positive refractive power, and a final lens group having positive refractive power, wherein the variable power group is provided with, in order from the object side, a first lens element having positive refractive power, a second lens element, and a third lens element, the second lens element has a convex shape on the object side, and the final lens group comprises a positive lens, the variable power optical system satisfying the following conditional expression:10&#x2266;&#x2266;45&#x2212;1.0&#x3c;(22)/(22)&#x3c;1.0where VdLg is the Abbe number of the positive lens of the final lens group with respect to the d line, R2a is the curvature radius of the object-side surface of the second lens element, and R2b is the curvature radius of the image-side surface of the third lens element.

In an image forming optical system which includes in order 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, a refractive index for a d-line of a positive single lens having the largest refractive power among all lenses in the second lens group, is the smallest of a refractive index of lenses in the second lens group.

Image forming optical system and electronic image pickup apparatus using the same

A zoom lens system according to the present invention includes a first lens group with negative refractive power, a second lens group with positive refractive power, a third lens group with positive refractive power, and a fourth lens group with negative refractive power which are arranged in turn from the object side toward the image side, and the zoom lens system is formed so that, in performing a zooming operation from the wide angle end position to the telephoto end position, the first lens group keeps still, the distance between the first and second lens groups becomes small, the distance between the second and third lens groups becomes wide, and the distance between the third and fourth lens groups becomes small.

Zoom lens system and image pickup device having the same

A variable power optical system includes, in order from the object side, a first lens group having negative refractive power, a variable power group having positive refractive power, and a final lens group having positive refractive power. The variable power group is provided with, in order from the object side, a first lens element having positive refractive power, a second lens element, and a third lens element. The second lens element has a convex shape on the object side. The final lens group includes a positive lens. The variable power optical system satisfies the following conditions:10&#x2266;&#x2266;45&#x2212;1.0&#x3c;(22)/(22)&#x3c;1.0where VdLg is the Abbe number of the positive lens of the final lens group with respect to the d line, Ris the curvature radius of the object-side surface of the second lens element, and Ris the curvature radius of the image-side surface of the third lens element.

An image forming optical system includes in order from an object side to an image surface, a first lens group having a positive refracting power, a second lens group having a negative refracting power, and a third lens group having a positive refracting power. At the time of zooming from a wide angle end to a telephoto end, a distance between the first lens group and the second lens group increases, and a distance between the second lens group and the third lens group decreases. The first lens group has a cemented lens which includes a first lens element E, a second lens element E, and a third lens element E. In the cemented lens, the first lens element Eis cemented to a surface on one side of the second lens element E, and the third lens element Eis cemented to another surface of the second lens element E. The first lens element Eis a negative lens, and the second lens element Eis a positive lens. The image forming optical system satisfies predetermined conditional expressions.

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Kanagawa, Japan

Takayuki Mimura