Fujifilm Corporation

Masato Kondo

Michio Cho

Taro Asami

Takayuki Noda

Toshiaki Katsuma

Ryoko Otomo

Toru Ito

Takuya Tanaka

Kazumi Koike

Tatsuyuki Ogino

Chikara Yamamoto

Takashi Suzuki

Tetsuya Ori

Hiroki Saito

Motoari Ota

A zoom lens consisting of, in order from an object side to an image side: a first lens group that has a positive refractive power; a second lens group that has a negative refractive power; and a subsequent group that has a plurality of lens groups, wherein: the zoom lens includes an aperture stop at a position closer to the image side than a lens surface closest to the image side in the second lens group, a lens group closest to the image side in the subsequent group includes at least one negative lens of which an object side lens surface is a concave surface being in contact with air, during zooming, a spacing between the first lens group and the second lens group changes, a spacing between the second lens group and the subsequent group changes, and spacings between all adjacent lens groups in the subsequent group change.

Zoom lens and imaging apparatus

The objective lens for an endoscope includes a stop, at least one lens which is disposed closer to an object side than the stop and of which an image-side lens surface is a concave surface, and at least one set of cemented lenses that is disposed closer to an image side than the stop; focusing on an object positioned at a nearest point from an object positioned at a farthest point is performed by movement of some lenses of an entire system along an optical axis; the objective lens for an endoscope has a total angle of view of 120° or more in a state where focusing on the object positioned at the farthest point is performed and in a state where focusing on the object positioned at the nearest point is performed; and the objective lens for an endoscope satisfies predetermined conditional expressions.

Objective lens for endoscope and endoscope

The imaging lens consists of, in order from the object side to the image side, a first lens group having a positive refractive power, a second lens group having a positive refractive power, and a third lens group. During focusing, only the second lens group moves. The second lens group includes at least four lenses. The imaging lens satisfies predetermined conditional expressions.

Imaging lens and imaging apparatus

An imaging lens consists of, in order from the object side, a first lens group, a stop, a positive second lens group, and a third lens group. During focusing, at least the second lens group moves and the third lens group does not move. The second lens group includes at least two negative lenses. The third lens group consists of one negative lens and one positive lens.

The imaging lens consists of, in order from the object side, a first positive lens group, a stop, a second positive lens group, and a third negative lens group. During focusing, the first lens group and the second lens group move integrally. The first lens group consists of three or less lenses. The first lens group includes a cemented lens in which a negative lens and a positive lens are cemented in order from the object side. The third lens group consists of, in order from the object side, a negative aspheric lens, a negative lens, and a positive lens. The lens closest to the image side in the second lens group is a biconvex lens, and the imaging lens satisfies a predetermined conditional expression regarding the radius of curvature of the surface of the biconvex lens.

The zoom lens consists of a positive first lens group, a negative second lens group moving during zooming, a positive third lens group moving during zooming, and a positive fourth lens group which does not move during zooming in order from an object side. Only the third lens group moves during focusing. A lens surface closest to an object is a convex surface. A conditional expression of 5&#x3c;TL/(Y&#xd7;ft)&#x3c;9.5 which is related to a total optical length TL at a telephoto end, a maximum image height Y, and a focal length ft of the entire system at the telephoto end in a state in which an object at infinity is in focus is satisfied.

The imaging lens consists of, in order from an object side: a first lens group that has a positive refractive power; a stop; a second lens group that has a refractive power; a third lens group that has a negative refractive power; and a fourth lens group that has a positive refractive power. The first lens group has, successively in order from a position closest to the object side, a negative meniscus lens that is convex toward the object side, a lens that is convex toward the object side, and a lens that is concave toward the object side. The third lens group consists of a negative lens. During focusing from an object at infinity to an object at a shortest distance, only the third lens group moves to an image side along an optical axis. The imaging lens satisfies a predetermined conditional expression relating to a focal length of the first lens group and a radius of curvature of an image side surface of a lens closest to the image side in the first lens group.

The imaging lens includes, in order from the object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a third lens group having a positive refractive power. During focusing, only the second lens group moves in the direction of the optical axis. A lens closest to the object side in the first lens group has a positive refractive power. The second lens group includes two or three lenses, a lens closest to the object side is a meniscus lens which is concave toward the object side and has a positive refractive power, and a lens adjacent thereto on the image side has a negative refractive power. A lens closest to the image side in the third lens group is a single lens which is concave toward the object side and has a negative refractive power. Further, predetermined Conditional Expression (1) is satisfied.

The imaging lens includes, in order from the object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a third lens group having a positive refractive power. During focusing, only the second lens group moves in the direction of the optical axis. A lens closest to the object side in the first lens group and a lens adjacent to the lens on the image side have positive refractive powers, and the second lens group includes two or three lenses. Further, predetermined Conditional Expressions (1), (2), (3a), and (3b) are satisfied.

The imaging lens consists of, in order from the object side, a first lens group Ghaving a positive power, a diaphragm, a second lens group Ghaving a positive power, and a third lens group G. Each of the lens groups includes three or more lenses. A positive lens is disposed on a most object side in the first lens group G, and a meniscus lens, which is concave toward the object side, is disposed to be closest to the object side in the second lens group G. During focusing from an infinite distance object to a close-range object, elements ranging from the first lens group Gto the second lens group Gintegrally move toward the object side, and the third lens group Gremains stationary. The imaging lens satisfies a conditional expression about a radius of curvature of an air lens of the first lens group G

An imaging lens is constituted essentially by six lenses, including: a first lens having a positive refractive power and is of a meniscus shape with a convex surface toward the object side; a second lens having a negative refractive power; a third lens; a fourth lens having a positive refractive power; a fifth lens having a negative refractive power and a concave surface toward the image side; and a sixth lens of a biconcave shape, provided in this order from the object side. The imaging lens satisfies a predetermined conditional formula.

Imaging lens and imaging apparatus equipped with the imaging lens

An imaging lens is constituted by, in order from the object side to the image side, a positive first lens group, a negative second lens group, and a positive third lens group. During focusing operations, the first lens group and the third lens group are fixed, while the second lens group moves. The first lens group has a cemented lens formed by cementing a positive lens and a negative lens together. The second lens group is constituted by two or fewer lenses. The third lens group is constituted by three or more lenses. The surface toward the object side of at least one of the first and second lenses from the object side within the third lens group is concave. A negative lens having a concave surface toward the object side is provided most toward the image side. A predetermined conditional formula is satisfied.

An imaging lens consists of five lenses, including: a first lens having a positive refractive power and a meniscus shape with a convex surface toward the object side, a second lens having a biconcave shape with the surface having the radius of curvature with the smaller absolute value toward the image side, a third lens having a meniscus shape with a convex surface toward the object side, a fourth lens having a negative refractive power and a meniscus shape with a convex surface toward the image side, and a fifth lens having a negative refractive power and a meniscus shape with a concave surface toward the image side, the image-side surface thereof having at least one inflection point, disposed in this order from the object side.

An imaging lens is constituted of five lenses, including, in order from the object side to the image side: a first lens having a positive refractive power, which is of a meniscus shape having a convex surface toward the object side; a second lens having a negative refractive power and a concave surface toward the image side; a third lens having a positive refractive power, which is of a meniscus shape having a convex surface toward the object side; a fourth lens having a negative refractive power; and a fifth lens having a negative refractive power and at least one inflection point on the surface thereof toward the image side. Predetermined conditional formulae are satisfied.

An imaging lens is essentially constituted by five lenses, including: a first lens of a biconvex shape; a second lens of a meniscus shape having a concave surface toward the image side; a third lens of a biconcave shape; a fourth lens of a meniscus shape having a convex surface toward the image side; and a fifth lens of a biconcave shape having at least one inflection point on the surface thereof toward the image side, provided in this order from the object side.

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Saitama-ken, Japan

Masato Kondo