A lens assembly includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens, all of which are arranged in order from an object side to an image side along an optical axis. The first lens is with positive refractive power and includes a convex surface facing the object side. The second lens is with negative refractive power and includes a concave surface facing the image side. The third lens is with refractive power and includes a convex surface facing the image side. The fourth, fifth, and sixth lenses are with refractive power. The lens assembly satisfies: 2 mm<f.sub.5+f.sub.6<35 mm, wherein f.sub.5 is an effective focal length of the fifth lens and f.sub.6 is an effective focal length of the sixth lens.

A lens assembly includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens, all of which are arranged in order from an object side to an image side along an optical axis. The first lens is with positive refractive power and includes a convex surface facing the object side. The second lens is with negative refractive power and includes a concave surface facing the image side. The third lens is with refractive power and includes a convex surface facing the image side. The fourth, fifth, and sixth lenses are with refractive power. The lens assembly satisfies: 2 mm<f.sub.5+f.sub.6<35 mm, wherein f.sub.5 is an effective focal length of the fifth lens and f.sub.6 is an effective focal length of the sixth lens.

The present invention relates to an objective for photographic applications, comprising, in a sequence from an object side end to an image side end, a first lens group having a positive refractivity with at least one lens, a second lens group having a negative refractivity with a single lens, a third lens group having a negative refractivity with a single lens and a fourth lens group having a positive refractivity with at least one lens, wherein the lenses of the second and third lens groups each have a concave surface which face one another and define an air lens, wherein f1 is the overall focal length of the lenses of the second and third lens groups and f2 is the focal length of the air lens, and wherein the relationship 5.0≤f1/f2≤9.0 is true.

A teleconverter lens consists essentially of, in order from the object side: a front group having a positive refractive power; and a rear group having a negative refractive power, wherein the front group and the rear group are separated from each other by the widest air space, the front group consists essentially of one positive lens having a convex surface toward the object side, and the rear group includes, in order from the object side, at least one negative lens having a concave surface toward the image side, and at least one positive lens having a convex surface toward the object side.

A teleconverter lens consists essentially of, in order from the object side: a front group having a positive refractive power; and a rear group having a negative refractive power, wherein the front group and the rear group are separated from each other by the widest air space, the front group consists essentially of one positive lens having a convex surface toward the object side, and the rear group includes, in order from the object side, at least one negative lens having a concave surface toward the image side, and at least one positive lens having a convex surface toward the object side.

An optical lens includes a first lens (L1), a second lens (L2), a third lens (L3), and a fourth lens (L4), which are successively coaxially arranged along the transmission direction of incident light, wherein the first lens (L1) and the fourth lens (L4) are negative meniscus lenses, the second lens (L2) is a positive meniscus lens, and the third lens (L3) is a positive plano-convex lens. The optical lens can be applied to an optical system of a laser processing device, when a utilized processing wavelength is different from a monitoring wavelength, the imaging chromatic aberration in a monitoring system may be eliminated, particularly when a wavelength of the far infrared region is utilized as a wavelength for laser processing. When using the red light wavelength as the monitoring wavelength, the monitoring system can achieve a better imaging effect, thus ensuring the quality of laser processing.

An optical imaging lens includes first, second, third, and fourth lens elements arranged in order from an object side to an image side along an optical axis. Each lens element has an object-side surface and an image-side surface. The first lens element has positive refracting power. The object-side surface of the first lens element has a convex portion in a vicinity of the optical axis and a convex portion in a vicinity of a periphery. The second lens element has negative refracting power. The object-side surface of the third lens element has a concave portion in a vicinity of a periphery. The image-side surface of the fourth lens element has a convex portion in a vicinity of a periphery.

An optical imaging lens includes first, second, third, and fourth lens elements arranged in order from an object side to an image side along an optical axis. Each lens element has an object-side surface and an image-side surface. The first lens element has positive refracting power. The object-side surface of the first lens element has a convex portion in a vicinity of the optical axis and a convex portion in a vicinity of a periphery. The second lens element has negative refracting power. The object-side surface of the third lens element has a concave portion in a vicinity of a periphery. The image-side surface of the fourth lens element has a convex portion in a vicinity of a periphery.

The present disclosure discloses an optical imaging lens assembly, and the optical imaging lens assembly includes, sequentially from an object side to an image side along an optical axis: a first lens having positive refractive power, and at least one subsequent lens having refractive power. An F-number Fno1 of the optical imaging lens assembly satisfies Fno1>3.5, where an object distance is finite, and an F-number Fno2 of the optical imaging lens assembly satisfies Fno2≥1.0, where the object distance is infinite.

An optical imaging system includes a first lens, a second lens, a third lens, and a fourth lens sequentially disposed from an object side toward an image side on an optical axis, and a reflecting member disposed closer to the object side, as compared to the first lens, and having a reflecting surface configured to change a path of light to be incident to the first to fourth lenses. The first to fourth lenses are disposed to be spaced apart from each other by a preset distance along the optical axis, and 1.3<TTL/BFL<3.5, where TTL is a distance from an object-side surface of the first lens to an imaging plane of an image sensor, and BFL is a distance from an image-side surface of the fourth lens to the imaging plane of the image sensor.