Multi-cameras and in particular dual-cameras comprising a Wide camera comprising a Wide lens and a Wide image sensor, the Wide lens having a Wide effective focal length EFL.sub.W and a folded Tele camera comprising a Tele lens with a first optical axis, a Tele image sensor and an OPFE, wherein the Tele lens includes, from an object side to an image side, a first lens element group G1, a second lens element group G2 and a third lens element group G3, wherein at least two of the lens element groups are movable relative to the image sensor along the first optical axis to bring the Tele lens to two zoom states, wherein an effective focal length (EFL) of the Tele lens is changed from EFL.sub.T,min in one zoom state to EFL.sub.T,max in the other zoom state, wherein EFL.sub.Tmin>1.5×EFL.sub.W and wherein EFL.sub.Tmax>1.5×EFL.sub.Tmin.

Multi-cameras and in particular dual-cameras comprising a Wide camera comprising a Wide lens and a Wide image sensor, the Wide lens having a Wide effective focal length EFL.sub.W and a folded Tele camera comprising a Tele lens with a first optical axis, a Tele image sensor and an OPFE, wherein the Tele lens includes, from an object side to an image side, a first lens element group G1, a second lens element group G2 and a third lens element group G3, wherein at least two of the lens element groups are movable relative to the image sensor along the first optical axis to bring the Tele lens to two zoom states, wherein an effective focal length (EFL) of the Tele lens is changed from EFL.sub.T,min in one zoom state to EFL.sub.T,max in the other zoom state, wherein EFL.sub.Tmin>1.5×EFL.sub.W and wherein EFL.sub.Tmax>1.5×EFL.sub.Tmin.

A variable-power optical system (ZL) is constituted by, in order from the object side and along the optical axis, the following: a first lens group (G1) that has a positive refractive power; a second lens group (G2); a third lens group (G3) that has a negative refractive power; and a rear group (GR) that includes a plurality of lens groups. When power is varied from the wide-angle end to the telephoto end, the interval between the first lens group and the second lens group increases, the interval between the second lens group and the third lens group increases, and the interval between the third lens group and a lens group in the rear group positioned closest to the object decreases, thus satisfying the following conditional equation:

0.10<D1/D2<1.80, where D1 is the length on the optical axis from the lens plane closest to the object of the first lens group to the lens plane closest to the image, and D2 is the length on the optical axis from the lens plane closest to the object of the second lens group to the lens plane closest to the image.

A variable-power optical system (ZL) is constituted by, in order from the object side and along the optical axis, the following: a first lens group (G1) that has a positive refractive power; a second lens group (G2); a third lens group (G3) that has a negative refractive power; and a rear group (GR) that includes a plurality of lens groups. When power is varied from the wide-angle end to the telephoto end, the interval between the first lens group and the second lens group increases, the interval between the second lens group and the third lens group increases, and the interval between the third lens group and a lens group in the rear group positioned closest to the object decreases, thus satisfying the following conditional equation:

0.10<D1/D2<1.80, where D1 is the length on the optical axis from the lens plane closest to the object of the first lens group to the lens plane closest to the image, and D2 is the length on the optical axis from the lens plane closest to the object of the second lens group to the lens plane closest to the image.

An endoscope magnification optical system includes, in order starting from an object side, a first lens group having positive power, a second lens group having positive power, and a third lens group including at least a meniscus lens with a concave surface facing the object side and a positive lens, and the endoscope magnification optical system is configured to magnify an optical image by moving at least the second lens group in an optical axis direction with respect to the first lens group, which is a fixed lens group, while a distance from a lens surface located the closest to the object of the first lens group to an image plane is kept constant.

An optical system includes a first unit having positive refractive power, a second unit having positive or negative refractive power and configured to move in focusing, and a third unit having negative refractive power in order from an object side to an image side. A distance between adjacent two of the units changes in focusing. When a distance on an optical axis from a lens surface closest to the object side to a lens surface closest to the image side is TL, a distance on the optical axis from a lens surface closest to the object side to a lens surface closest to the image side in the third unit is TL3, a sum of thicknesses, on the optical axis, of lenses in the third unit is SD3, and the largest of the thicknesses of the lenses in the third unit is DM3, the optical system satisfies predetermined conditional inequalities.

Provided is a camera optical lens including first to fifth lenses. The camera optical lens satisfies: 0.35≤f1/f≤0.65; 2.00≤f5/f≤4.00; 0.90≤d6/d8≤1.30; and −10.00≤(R5+R6)/(R5−R6)≤−2.00, where f denotes a focal length of the camera optical lens; f1 denotes a focal length of the first lens; f5 denotes a focal length of the fifth lens; d6 denotes an on-axis distance from an image side surface of the third lens to an object side surface of the fourth lens; d8 denotes an on-axis distance from an image side surface of the fourth lens to an object side surface of the fifth lens; and R5 and R6 respectively denote curvature radiuses of an object side surface and an image side surface of the third lens. The camera optical lens can achieve good optical performance while satisfying design requirements for ultra-thin, long-focal-length lenses having large apertures.

An optical imaging system includes five lens elements, the five lens elements being, in order from an object side to an image side: a first lens element having positive refractive power; a second lens element having negative refractive power; a third lens element having positive refractive power; a fourth lens element having positive refractive power; and a fifth lens element having negative refractive power.

An optical imaging system includes five lens elements, the five lens elements being, in order from an object side to an image side: a first lens element having positive refractive power; a second lens element having negative refractive power; a third lens element having positive refractive power; a fourth lens element having positive refractive power; and a fifth lens element having negative refractive power.

The present disclosure discloses an optical imaging lens assembly including, sequentially from an object side to an image side along an optical axis, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens. The first lens has a positive refractive power; the second lens has a negative refractive power; the third lens has a negative refractive power; the fourth lens has a refractive power, and an image-side surface thereof is a convex surface; the fifth lens has a negative refractive power, and an object-side surface thereof is a concave surface; and the sixth lens has a refractive power, and an object-side surface thereof is a concave surface. Here, an effective focal length f3 of the third lens and an effective focal length f of the optical imaging lens assembly satisfy −3<f3/f<−1.5.