An optical lens including a first lens group and a second lens group is provided. The first lens group is arranged between a magnified side and a minified side. The first lens group includes three lenses. A surface of a second lens facing to the minified side is a convex aspherical surface. The second lens group includes three lenses. Each of the first lens group and the second lens group includes at least one aspherical lens.

The zoom lens has an aperture stop arranged between the second lens unit and the fourth lens unit. During zooming from the wide angle end to the telephoto end, the distances between the lens units vary in such a way that the distance between the first lens unit and the second lens unit is larger at the telephoto end than at the wide angle end, the distance between the second lens unit and the third lens unit is smaller at the telephoto end than at the wide angle end, and the distance between the fourth lens unit and the fifth lens unit is larger at the telephoto end than at the wide angle end. The zoom lens satisfies the following conditional expression (1):
3.5≦LTL.sub.w/IH.sub.t≦8.9  (1).

A variable magnification optical system consists of a first lens-group having negative refractive-power, a stop and a second lens-group having positive refractive-power in this order from an object-side. The first lens-group includes an L11 negative meniscus lens, an L12 negative lens and a C11 cemented lens, in which a biconcave lens and a positive lens are cemented together in this order from the object-side, in this order from the object-side. The second lens-group includes an L21 positive lens that is arranged closest to the object-side and includes at least one aspheric surface, and an object-side surface of which is convex, and only two cemented lenses toward an image-side of the L21 positive lens, and each of which consists of a negative lens and a positive lens cemented together in this order from the object-side. The following conditional expressions (1) and (2) are satisfied:
−1.0<Rf11/Rf12<0.7  (1); and
55.0<νdave1  (2).

A wide angle zoom lens includes sequentially from the object side, a first lens group having a negative refractive power overall and three lenses, including first to third lenses, having a negative refractive power and disposed farthest on the object side; a second lens group having a positive refractive power overall and one or more sets of cemented lenses; and a third lens group having a negative refractive power. This ultra wide angle zoom lens varies intervals between the first lens group, the second lens group, and the third lens group on the optical axis to zoom from the wide angle end to the telephoto end and satisfies given conditions to thereby enable a high zoom ratio, large diameter, and high resolution.

An optical assembly for a wide field of view digital camera includes, from object end to image end, first and second optical groups separated by an aperture stop. The optical assembly is configured to provide images with TV distortion that is less than 16. The first optical group includes two or more lens elements, including a first lens element having a largest diameter among the multiple lens elements to collect light at said wide field of view. The second optical group includes a doublet, which is configured to compensate for oblique aberrational error, and an aspheric lens element, which is configured to compensate for astigmatism error.

A lens system in the present disclosure includes: a first lens group that is moved toward an image side along an optical axis in focusing from a far-object in-focus state to a near-object in-focus state, and has positive optical power; and a second lens group that is disposed on the image side relative to the first lens group and has optical power. The lens system satisfies the following conditions (1) and (2).

0.5<|fg1/WD|<2.0  (1)

20<|fg2/f|<700  (2) where fg1 is a focal length of the first lens group, WD is a distance, on the optical axis, from an object surface to a lens surface located closest to an object side of the first lens group, fg2 is a focal length of the second lens group, and f is a focal length of the lens system under the far-object in-focus state.

An optical system (LS) has a lens (L11) that satisfies the following conditional expressions.

−0.010<ndLZ−(2.015−0.0068×νdLZ)

50.00<νdLZ<65.00 0.545<θgFLZ

−0.010<θgFLZ−(0.6418−0.00168×νdLZ) where ndLZ is the refractive index to the d line of the lens, νdLZ is the Abbe number with respect to the d line of the lens, and θgFLZ is the partial dispersion ratio of the lens.

This optical system (LS) has an aperture diaphragm (S) and a negative lens (L4) disposed closer to an object side than the aperture diaphragm (S) and satisfies the following conditional expression.

−0.010<ndN1−(2.015−0.0068×νdN1),

50.00<νdN1<65.00, 0.545<θgFN1,

−0.010<θgFN1−(0.6418−0.00168×νdN1).

Where, ndN1 is a refractive index of the negative lens with respect to a d-line, vdN1 is an Abbe number of the negative lens based on the d-line, and θgFN1 is a partial dispersion ratio of the negative lens.

An imaging lens which uses a larger number of constituent lenses for higher performance and features a low F-value, low-profile design and a wide field of view. Designed for a solid-state image sensor, the imaging lens includes constituent lenses arranged in order from an object side to an image side: a first positive refractive power lens; a second negative refractive power lens; a third lens; a fourth lens; a fifth lens; a sixth lens having a concave image-side surface near an optical axis; and a seventh negative refractive power lens.

An imaging optical system includes a positive or negative first lens group including a negative lens element closest to the object, a diaphragm, and a positive second lens group. The negative lens element closest to the object has an object-side aspherical surface including a paraxial convex surface, a paraxial curvature that is the greatest within the effective aperture, and a portion within the effective aperture having a curvature less than ½ of the paraxial curvature. These conditions are satisfied:

R1/f<1.35

D1/f>0.4

−2.5<f1/f<−1.3

V>56 “f” designates the overall focal length; f1, R1 and D1 respectively designate the focal length, paraxial radius of curvature of an object-side surface, and thickness, of the negative lens element closest to the object; and V designates the Abbe number regarding the d-line of a lens element, within the second lens group, closest to the diaphragm.