Ricoh Company, Ltd.

Ricoh Imaging Company, Ltd.

Pentax Ricoh Imaging Company, Ltd.

Tomoya Koga

Takashi Enomoto

Yoshifumi Sudoh

Takahiro Nakayama

Junichi Fujisaki

A zoom lens system includes a first lens group; a second lens group; and a subsequent lens group arranged in that order from the object side. The second lens group consists of a second lens group-a, a second lens group-b, and a second lens group-c arranged in that order from the object side. A distance between the first lens group and the second lens group increases and a distance between the second lens group and the subsequent lens group decreases during a change in magnification from a short focal length end to a long focal length end. During a change in focus from infinity to a short distance, the second lens group-b is movable to the image side, and a distance between the second lens group-a and the second lens group-b and a distance between the second lens group-b and the second lens group-c are changeable.

Zoom lens system, lens barrel, and imaging device

A zoom lens includes a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a rear group, sequentially from an object side. Intervals between lens groups varies when changing magnification. A lens group having a highest negative refractive power among a lens group having a negative refractive power in the rear group is a focusing lens group GF configured to move toward an image side when focusing from infinity to a close range. A lens group GFF having a positive refractive power and arranged adjacent to an object side of the focusing lens group GF among a lens group having a positive refractive power included in the rear group includes a positive lens component L1 positioned on a most image side, which includes a positive lens L1P having a refractive index NdL1P, and a conditional expression (1) 1.85<NdL1P is satisfied.

Zoom lens, lens barrel, and imaging apparatus

A zoom lens includes a first lens group having positive refractive power, a second lens group having negative refractive power, and a rear group. The second lens group consists of a second sub-first lens group having positive or negative power, and a second sub-second lens group having negative power. The second sub-second lens group consists of, sequentially from the object side toward the image: a positive second-first lens component; a negative second-second lens component; and a negative second-third lens component. During zooming from a short focal length end to a long focal length end, a distance between the first lens group and the second lens group increases, and a distance between the second lens group and the rear group decreases. A part of the second lens group is movable in a direction perpendicular to an optical axis during correction of image blurring.

Zoom lens, lens barrel, and image-capturing device

A zoom lens includes a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a rear group, sequentially from an object side. Intervals between lens groups varies when changing magnification. A lens group having a highest negative refractive power among a lens group having a negative refractive power in the rear group is a focusing lens group GF configured to move toward an image side when focusing from infinity to a close range. A lens group GFF having a positive refractive power and arranged adjacent to an object side of the focusing lens group GF among a lens group having a positive refractive power included in the rear group includes a positive lens component L1 positioned on a most image side, which includes a positive lens L1P having a refractive index NdL1P, and a conditional expression (1) 1.85&#x3c;NdL1P is satisfied.

A zoom lens satisfies Conditional Expression (1) as follows:&#x2212;20&#x3c;&#x3c;1,&#x2003;&#x2003;(1)Twt is a moving amount of the second lens group during zooming from the short focal-length end to the long focal-length end, a moving amount to the object side being indicated by a positive sign, a moving amount to an image side being indicated by a negative sign, andTwm is a moving amount of the second lens group during zooming from the short focal-length end to an intermediate focal length, a moving amount to the image side being indicated by a negative sign,the intermediate focal length being expressed by fm=(fw&#xb7;ft), where fw is a focal length of a whole system at the short focal-length end, and ft is a focal length of the whole system at the long focal-length end.

Zoom lens system, interchangeable lens, and imaging apparatus

A zoom lens system includes a first lens group having positive refractive power; a second lens group having negative refractive power; and a rear group, the first lens group, arranged in that order from an object side. The second lens group includes a second lens group-a having negative refractive power and a second lens group-b having negative refractive power arranged in that order from the object side. During a change in a focus from a short focal length end to a long focal length end to change a magnification power, a distance between the first lens group and the second lens group-a increases, a distance between the second lens group-a and the second lens group-b is changeable or stationary, and a distance between the second lens group-b and the rear lens group decreases.

Zoom lens system and imaging apparatus provided with the same

A zoom lens system includes a positive first lens group, a negative second lens group, a positive intermediate lens group, and a negative image-side lens group. Upon zooming from the short to long focal length extremities, a distance between the first and second lens groups increases, and a distance between the second and intermediate lens groups decreases. The image-side lens group consists of two lens elements. The following conditions are satisfied:&#x2212;6.0&#x3c;f1/f2&#x3c;&#x2212;4.3,&#x2212;5.4&#x3c;f1/fIMG&#x3c;&#x2212;3.9, and0.3&#x3c;D2/fw&#x3c;3.0,

Zoom lens system

A zoom lens system includes a positive first lens group, and a rear lens group behind the first lens group, in that order from the object side. The first lens group includes at least one positive single lens element, a negative meniscus lens element having a convex surface on the object side, and at least one positive lens element, in that order from the object side. A distance between the first lens group and the rear lens group increases upon zooming from the short to long focal length extremities. The following conditions (1) and (2) are satisfied:1/&#x3c;&#x2212;1.50&#x2003;&#x2003;(1), and65&#x3c;&#x3bd;p&#x2003;&#x2003;(2),wherein fG1 designates the focal length of the first lens group, fn designates the focal length of the negative meniscus lens element, and &#x3bd;pdesignates the average value of the Abbe numbers with respect to the d-line of the positive lens elements.

The objective of the present invention is to provide a zoom lens system having an f-number of approximately 1.3 at the wide extremity, a half angle-of-view of 75 degrees, and a zoom ratio of approximately 3:1. The solution to this objective is to provide a zoom lens system including a first lens group, having a negative refractive power, a diaphragm, and a second lens group, having a positive refractive power, in that order from the object side; wherein the first lens group and the second lens group move in the optical axis direction so that the distance therebetween decreases upon zooming from the wide-angle extremity to the telephoto extremity.

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Saitama, Japan

Tomoya Koga