37results about How to "Excellently corrected" patented technology

Provided is a small-sized five-element image pickup lens which ensures a sufficient lens speed of about F2 and exhibits various aberrations being excellently corrected. The image pickup lens is composed of, in order from the object side, a first lens with a positive refractive power, including a convex surface facing the object side; a second lens with a negative refractive power, including a concave surface facing the image side; a third lens with a positive or negative refractive power; a fourth lens with a positive refractive power, including a convex surface facing the image side; and a fifth lens with a negative refractive power, including a concave surface facing the image side. The image-side surface of the fifth lens has an aspheric shape, and includes an inflection point at a position excluding an intersection point with the optical axis.

A zoom lens system having a high zoom ratio and excellently correcting various aberrations over an entire zoom range between a wide angle end and a telephoto end to obtain high optical performance in the entire zoom range, 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, and a fourth lens unit. The fourth lens unit includes a front subunit and a rear subunit, the rear subunit being constituted by two negative lenses and at least three positive lenses. The rear subunit includes a first rear-subunit and a second rear-subunit. Each of the first rear-subunit and the second rear-subunit includes a negative lens and at least one positive lens. Lens materials are suitably set for the first rear-subunit and the rear second-subunit.

A rear attachment lens changes a focal-length of an entire lens-system, in which the rear attachment lens has been attached to a main-lens, to a longer focal-length-side than a focal-length of the main-lens by being attached to an image-side of the main-lens. The rear attachment lens consists essentially of a first-lens-group and a second-lens-group in this order from an object-side. The first-lens-group consists essentially of a negative lens and a positive lens in this order from the object-side. The second-lens-group consists essentially of at least one negative lens and at least one positive lens, and a lens closest to an image-side in the second lens-group is a positive lens. When an Abbe number for d-line and a partial dispersion ratio between g-line and F-line of the negative lens in the first-lens-group are νd1 and θgF1, respectively, conditional expression (1): νd1>62 and conditional expression (2): 0.64<θgF1+0.001625 ×νd1<0.69 are satisfied.

A zoom lens system having a high zoom ratio and excellently correcting various aberrations over an entire zoom range between a wide angle end and a telephoto end to obtain high optical performance in the entire zoom range, 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, and a fourth lens unit. The fourth lens unit includes a front subunit and a rear subunit, the rear subunit being constituted by two negative lenses and at least three positive lenses. The rear subunit includes a first rear-subunit and a second rear-subunit. Each of the first rear-subunit and the second rear-subunit includes a negative lens and at least one positive lens. Lens materials are suitably set for the first rear-subunit and the rear second-subunit.

A lens system comprising, in order from an object side: a first lens group G1; and a second lens group G2 having positive refractive power; the first lens group G1 including a sub-lens group GS11 having positive refractive power, and a sub-lens group GS12 having negative refractive power, the sub-lens group GS12 having negative refractive power including a meniscus lens having a convex surface facing the object side, given conditions being satisfied: an antireflection coating being formed on at least one optical surface in the first lens group G1 and the second lens group G2, and the antireflection coating including at least one layer formed by a wet-process, thereby providing a lens system having high optical performance with excellently correcting various aberrations and suppressing ghost images and flare, and an optical apparatus equipped therewith.

A zoom lens system, in which chromatic aberration, spherical aberration, and coma may be excellently corrected in a balanced manner so as to obtain excellent optical performance over an entire zoom range, 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; and a rear lens group including a lens unit having a positive refractive power, in which: at least one of the first lens unit and the second lens unit is moved for zooming so that an interval therebetween at a telephoto end is larger than an interval at a wide angle end; the first lens unit includes at least one negative lens; and an Abbe number (νd1n) and a partial dispersion ratio (θgF1n) of a material of the at least one negative lens are appropriately set.

A lens for projection substantially consists of a negative first lens with its concave surface facing a reduction side, a positive second lens with its concave surface facing the reduction side, a negative third lens with its concave surface facing a magnification side, a positive fourth lens with its convex surface facing the reduction side, a positive fifth lens and a positive sixth lens in this order from the magnification side. The reduction side is telecentric. The following conditional formulas (1) and (2) about refractive power P4 of a reduction-side surface of the second lens, refractive power P5 of a magnification-side surface of the third lens, and focal length f of an entire system are satisfied:−3.0≦1 / (P4×f)≦−0.4   (1); and−2.0≦1 / (P5×f)≦−0.2   (2).

Provided is an optical system in which chromatic aberrations can be excellently corrected in spite of environmental changes, to thereby maintain high optical performance. The optical system includes: a plurality of optical elements each having refractive surfaces located in a light incident side and a light exit side; and an aperture stop. A focal length, an Abbe number of a material, and an extraordinary partial dispersion ratio of each of an l-th optical element and an r-th optical element which satisfy a condition related to the extraordinary partial dispersion ratio are suitably set.

A rear attachment lens changes a focal-length of an entire lens-system, in which the rear attachment lens has been attached to a main-lens, to a longer focal-length-side than a focal-length of the main-lens by being attached to an image-side of the main-lens. The rear attachment lens consists essentially of a first-lens-group and a second-lens-group in this order from an object-side. The first-lens-group consists essentially of a negative lens and a positive lens in this order from the object-side. The second-lens-group consists essentially of at least one negative lens and at least one positive lens, and a lens closest to an image-side in the second lens-group is a positive lens. When an Abbe number for d-line and a partial dispersion ratio between g-line and F-line of the negative lens in the first-lens-group are νd1 and θgF1, respectively, conditional expression (1): νd1>62 and conditional expression (2): 0.64<θgF1+0.001625 ×νd1<0.69 are satisfied.

A variable magnification optical system includes a positive first lens group, a negative second lens group, a stop, a positive third lens group and a positive fourth lens group, which are in this order from an object side. The first lens group, the stop and the third lens group are fixed, but the second lens group and the fourth lens group move in an optical axis direction during magnification change. The fourth lens group has a focusing function. The third lens group includes at least an aspherical surface, and consists of, in the following order from the object side, a positive lens and a cemented lens of a positive lens and a double-concave lens cemented together. The variable magnification optical system satisfies a predetermined formula.

An imaging lens consists of a first lens-group consisting of a positive lens with its surface that has the smaller absolute value of a curvature-radius facing an object-side, a positive lens in meniscus-shape with its convex-surface facing the object-side, a positive lens with its surface that has the smaller absolute value of a curvature-radius facing the object-side, and a negative lens with its surface that has the smaller absolute value of a curvature-radius facing an image-side, an aperture stop, a second lens-group consisting of a negative lens with its surface that has the smaller absolute value of a curvature-radius facing the object-side, a positive lens with its surface that has the smaller absolute value of a curvature-radius facing the image-side, and a positive lens, and a third lens-group consisting of a positive lens and a negative lens in this order from the object-side. A predetermined conditional expression is satisfied.

A zoom lens consists of a first lens-group having positive refractive-power, a second lens-group having negative refractive-power, a third lens-group having positive refractive-power, a fourth lens-group having negative refractive-power, and a fifth lens-group having positive refractive-power in this order from an object-side. The third lens-group includes a cemented lens closest to an image-side consisting of a negative lens and a positive lens in this order from the object-side, and a cemented surface of which is convex toward the object-side. Further, distances between the lens-groups change, and the fifth lens-group is fixed, and at least the first lens-group and the fourth lens-group move in such a manner that the first lens-group and the fourth lens-group are located closer to the object-side at a telephoto-end than their positions at a wide-angle-end, respectively, when magnification is changed from the wide-angle-end to the telephoto-end. Further, the following conditional expression is satisfied:3.50<|D1| / |D4|<8.00  (1).

A zoom lens includes, in order from an object side to an image side, a positive first lens unit, a negative second lens unit, an aperture stop, a positive third lens unit, and a positive fourth lens unit. The third lens unit includes, in that order, a positive first lens sub-unit, and a negative second lens sub-unit. The second lens sub-unit is movable in a direction having a component perpendicular to an optical axis to change an image forming position in a direction perpendicular to the optical axis. A distance on the optical axis between the aperture stop and the third lens unit at a wide-angle end, a composite focal length of the first lens unit and the second lens unit at the wide-angle end, a focal length of the first lens sub-unit, and a focal length of the second lens sub-unit are appropriately set.

An eyepiece lens consists essentially of a first lens having positive refractive power, a second lens having negative refractive power, a third lens having positive refractive power, and a fourth lens having positive refractive power in this order from an observation object side. Conditional expression (1): −3.5<f / fA<0.0 is satisfied, wheref: a focal length of an entire system, andfA: a combined focal length of the first lens and the second lens.

A lens for projection substantially consists of a negative first lens with its concave surface facing a reduction side, a positive second lens with its concave surface facing the reduction side, a negative third lens with its concave surface facing a magnification side, a positive fourth lens with its convex surface facing the reduction side, a positive fifth lens and a positive sixth lens in this order from the magnification side. The reduction side is telecentric. The following conditional formulas (1) and (2) about refractive power P4 of a reduction-side surface of the second lens, refractive power P5 of a magnification-side surface of the third lens, and focal length f of an entire system are satisfied:−3.0≦1 / (P4×f)≦−0.4  (1); and−2.0≦1 / (P5×f)≦−0.2  (2).

Providing a zoom lens system with a vibration reduction function excellently correcting aberrations with accomplishing compact, lightweight, and slim upon being accommodated, and to provide an optical apparatus using the zoom lens system. The system consists of, in order from an object, a first group having negative power, a second group having positive power. Upon zooming from a wide-angle end to a telephoto end, a distance between the first group and the second group decreases. The first group consists of, in order from the object, a first lens having negative power and a second lens having positive power. The second group consists of, in order from the object, a third lens having positive power, a fourth lens having negative power, and a fifth lens having positive power. An image blur is corrected by shifting the second group as a whole in a direction substantially perpendicular to the optical axis.

An imaging lens consists of a first lens group, a second lens group, an aperture stop and a third lens group that has positive refractive power in this order from an object side. The first lens group consists of an L11 lens having positive refractive power, an L12 lens having negative refractive power, an L13 meniscus lens having negative refractive power with its concave surface facing an image side, an L14 lens having negative refractive power with its concave surface facing the object side and two or three lenses, each having positive refractive power, in this order from the object side. The second lens group consists of an L2p lens having positive refractive power and an L2n lens having negative refractive power.

An imaging lens consists of a negative first lens, a negative second lens, a third lens of a plano-convex shape having a convex surface directed toward an object side or of a positive meniscus shape having a convex surface directed toward the object side, and a fourth lens of a plano-convex shape having a convex surface directed toward an image side or of a positive meniscus shape having a convex surface directed toward the image side, which are arranged in this order from the object side. Further, the following conditional formula (3) is satisfied:1.0<|f2 / f|<2.6  (3), wheref: a focal length of an entire system, andf2: a focal length of the second lens.