Abstract: A zoom lens includes a first lens group, a second lens group, a third lens group, a fourth lens group and an aperture. The first lens group, the second lens group, the third lens group and the fourth lens group are sequentially arranged in a direction. The aperture is located between the second lens group and the third lens group. When the zoom lens performs a zoom operation, the first lens group and the third lens group are fixed and the second lens group and the fourth lens group are moved, and a moving distance of the fourth lens group on an optical axis of the zoom lens is less than 5 mm.

Abstract: An optical lens includes a first lens group with a negative refractive power, an aperture stop, and a second lens group with a positive refractive power. The first lens group includes a first aspheric lens and a second aspheric lens. The optical lens satisfies the conditions: 3.5>RT1>2.5 and 3.5>RT2>2.6, where RT1 is a ratio of a maximum axial thickness to a minimum axial thickness within a clear aperture of the first aspheric lens, and RT2 is a ratio of a maximum axial thickness to a minimum axial thickness within a clear aperture of the second aspheric lens.

Abstract: A zoom lens includes a first lens group, a second lens group, a third lens group, a fourth lens group and an aperture. The first lens group, the second lens group, the third lens group and the fourth lens group are sequentially arranged in a direction. The aperture is located between the second lens group and the third lens group. When the zoom lens performs a zoom operation, the first lens group and the third lens group are fixed and the second lens group and the fourth lens group are moved, and a moving distance of the fourth lens group on an optical axis of the zoom lens is less than 5 mm.

Abstract: A telecentric lens including a first lens group, an aperture stop, and a second lens group arranged in order from a magnified side to a minified side is provided. The first lens group has an outmost lens facing the magnified side, and the second lens group has an outmost lens facing the minified side. At least one of the outmost lens of the first lens group and the outmost lens of the second lens group is formed of glass. At least one of the first lens group and the second lens group has a lens having negative refractive power and being composed of plurality of lenses being mutually contacted to each other. The condition: TTL<100 mm is satisfied, wherein TTL denotes a length measured along an optical axis and between two outmost opposite lens surfaces of the telecentric lens.

Abstract: A zoom lens including a first lens group, a second lens group, and a third lens group is provided. The first lens group is disposed between an object side and an image side and has at least one aspheric surface. The second lens group has a positive refractive power and is disposed between the first lens group and the image side. The third lens group has a positive refractive power and is disposed between the second lens group and the image side. The third lens group has at least one aspheric surface. The third lens group is suitable to move relative to the second lens group for focusing.

Abstract: A telecentric lens including a first lens group, an aperture stop, and a second lens group arranged in order from a magnified side to a minified side is provided. The first lens group has an outmost lens facing the magnified side, and the second lens group has an outmost lens facing the minified side. At least one of the outmost lens of the first lens group and the outmost lens of the second lens group is formed of glass. At least one of the first lens group and the second lens group has a lens having negative refractive power and being composed of plurality of lenses being mutually contacted to each other. The condition: TTL<100 mm is satisfied, wherein TTL denotes a length measured along an optical axis and between two outmost opposite lens surfaces of the telecentric lens.

Abstract: A zoom lens includes a first lens group with a negative refractive power, a second lens group with a positive refractive power, and an aperture stop disposed in and movable with the second lens group. Each of the first lens group and the second lens group moves individually. The zoom lens further includes a doublet lens disposed on a first side of the aperture stop and between the first lens group and the aperture stop, and at most two lenses including at least one aspheric lens are disposed on a second side of the aperture stop.

Abstract: An image-space telecentric lens includes, in order from a magnified side to a minified side, a first lens group of negative refractive power, an aperture stop, and a second lens group of positive refractive power. The first lens group has at least one aspheric surface, and the second lens group has at least one aspheric surface. The second lens group has a cemented lens of positive refractive power, and the cemented lens is nearest the aperture stop as compared with other lens in the second lens group. The image-space telecentric lens satisfies the condition: TT<100 mm, where TT denotes a length measured along an optical axis and between two outermost opposite lens surfaces of the image-space telecentric lens.

Abstract: A zoom lens system includes a first lens group of negative refractive power and a second lens group of positive refractive power. The first lens group includes a first lens of negative refractive power, and the second lens group is disposed between the first lens group and a reduced side and includes in order from a magnified side to the reduced side a second lens of positive refractive power, a third lens of positive refractive power, a fourth lens of negative refractive power, and a fifth lens of positive refractive power. At least one of the first lens to the fifth lens is an aspherical lens having at least one aspherical surface.

Abstract: An optical lens includes a first lens group with a negative refractive power, an aperture stop, and a second lens group with a positive refractive power. The first lens group includes a first aspheric lens and a second aspheric lens. The optical lens satisfies the conditions: 3.5>RT1>2.5 and 3.5>RT2>2.6, where RT1 is a ratio of a maximum axial thickness to a minimum axial thickness within a clear aperture of the first aspheric lens, and RT2 is a ratio of a maximum axial thickness to a minimum axial thickness within a clear aperture of the second aspheric lens.

Abstract: An optical lens includes a first lens group and a second lens group. The first lens group is disposed between a magnified side and a minified side and has a negative refractive power. The second lens group is disposed between the first lens group and the minified side and has a positive refractive power. The optical lens is capable of forming an image at the magnified side. F/H>0.52, where F is an effective focal length, and H is an image height. A viewing angle is greater than 116.7 degrees.

Abstract: A zoom lens system includes a first lens group of negative refractive power and a second lens group of positive refractive power. The first lens group includes a first lens of negative refractive power, and the second lens group is disposed between the first lens group and a reduced side and includes in order from a magnified side to the reduced side a second lens of positive refractive power, a third lens of positive refractive power, a fourth lens of negative refractive power, and a fifth lens of positive refractive power. At least one of the first lens to the fifth lens is an aspherical lens having at least one aspherical surface.

Abstract: A zoom lens arranged along an optical axis includes a first lens group and a second lens group. The second lens group has at least one aspheric lens. The first lens group moves toward an image side and the second lens group moves away from the image side along the optical axis during zooming. The first lens group is moved for focusing, and the second lens group is moved for zooming.

Abstract: A zoom lens including a first lens group and a second lens group is provided. Refractive powers of the first lens group and the second lens group are respectively negative and positive. The first lens group includes a first lens, a second lens, and a third lens arranged in sequence from an object side to an image side. The second lens group is disposed between the first lens group and the image side, and includes a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens arranged in sequence from the object side to the image side. The zoom lens satisfies ?2.4<f1/fw<?1.0, wherein f1 is the effective focal length of the first lens group, and fw is the effective focal length of the zoom lens at a wide end.

Abstract: An optical lens system includes, in order from a magnified side to a minified side, a first lens group and a second lens group. The first lens group of negative refractive power has at least one aspheric surface, and the second lens group of positive refractive power has at least one aspheric surface. Each of the lenses in the optical lens system is a singlet lens, and the condition: TE(?=365)>70% is satisfied, where TE(?=365) denotes an overall transmittance of all of the lenses in the optical lens system measured at a wavelength of 365 nm.

Abstract: A zoom lens including a first lens group, a second lens group, and a third lens group is provided. The first lens group is disposed between an object side and an image side and has at least one aspheric surface. The second lens group has a positive refractive power and is disposed between the first lens group and the image side. The third lens group has a positive refractive power and is disposed between the second lens group and the image side. The third lens group has at least one aspheric surface. The third lens group is suitable to move relative to the second lens group for focusing.

Abstract: A zoom lens including a first lens group, a second lens group, a third lens group, and a fourth lens group with positive, negative, positive, and positive refractive powers respectively arranged in sequence from an object side to an image side is provided. The first lens group includes a first lens and a second lens. The second lens group includes a third lens, a fourth lens, and a fifth lens. The third lens group includes a sixth lens. The fourth lens group includes a seventh lens, an eighth lens, and a ninth lens. The first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, and the ninth lens respectively having negative, positive, negative, negative, positive, positive, positive, negative, and positive refractive powers are arranged in sequence from the object side to the image side.

Abstract: An optical lens includes a first lens group and a second lens group. The first lens group is disposed between a magnified side and a minified side and has a negative refractive power. The second lens group is disposed between the first lens group and the minified side and has a positive refractive power. The optical lens is capable of forming an image at the magnified side. F/H>0.52, where F is an effective focal length, and H is an image height. A viewing angle is greater than 116.7 degrees.

Abstract: A zoom lens including a first lens group, a second lens group, a third lens group, and a fourth lens group with positive, negative, positive, and positive refractive powers respectively arranged in sequence from an object side to an image side is provided. The first lens group includes a first lens and a second lens. The second lens group includes a third lens, a fourth lens, and a fifth lens. The third lens group includes a sixth lens. The fourth lens group includes a seventh lens, an eighth lens, and a ninth lens. The first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, and the ninth lens respectively having negative, positive, negative, negative, positive, positive, positive, negative, and positive refractive powers are arranged in sequence from the object side to the image side.

Abstract: A fixed focal length lens includes a first lens group and a second lens group. The first lens group is disposed between a magnified side and a minified side and has a negative refractive power. The second lens group is disposed between the first lens group and the minified side and has a positive refractive power. The fixed focal length lens satisfies F/H>0.52, where F is an effective focal length of the fixed focal length, and H is an image height.