An image capturing lens system includes four lens groups which include eight lens elements. The four lens groups are, in order from an object side to an image side: first, second, third and fourth lens groups. The eight lens elements are, in order from the object side to the image side: first, second, third, fourth, fifth, sixth, seventh and eighth lens elements. The first and second lens elements respectively have positive and negative refractive power. At least one lens element in the second through fourth lens groups has an inflection point. A focal length of the image capturing lens system is varied by changing axial distances between the four lens groups in a zooming process. The second lens group is moved relative to the first lens group along an optical axis in the zooming process. The image capturing lens system has a long-focal-length end and a short-focal-length end.

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 focal length lens system includes: first to fourth lens groups alternately having negative and positive refractive power; and an aperture stop; the first to fourth lens group being arranged to allow a space between the first and second lens groups to be decreased and spaces between the second and third lens groups and between the third and fourth lens groups to be varied, the third lens group travelling to allow image-plane position variation caused by subject position variation to be compensated and satisfying a following conditional expression,
0.05<Da/R3a<0.5  (1) where Da is a distance from the aperture stop to a most image-sided lens surface in the third lens group in the wide end state, and R3a is a curvature radius of the most-image sided lens surface in the third lens group.

A variable focal length lens system includes: first to fourth lens groups alternately having negative and positive refractive power; and an aperture stop; the first to fourth lens group being arranged to allow a space between the first and second lens groups to be decreased and spaces between the second and third lens groups and between the third and fourth lens groups to be varied, the third lens group travelling to allow image-plane position variation caused by subject position variation to be compensated and satisfying a following conditional expression,
0.05<Da/R3a<0.5  (1) where Da is a distance from the aperture stop to a most image-sided lens surface in the third lens group in the wide end state, and R3a is a curvature radius of the most-image sided lens surface in the third lens group.

Digital cameras comprising a lens assembly comprising N lens elements L.sub.1-L.sub.N starting with Li on an object side, wherein N is >4, an image sensor having a sensor diagonal S.sub.D, and a pop-out mechanism that controls a largest air-gap d between two consecutive lens elements within lens elements L.sub.1 and L.sub.N to bring the camera to an operative pop-out state and a collapsed state, wherein the lens assembly has a total track length TTL in the operative pop-out state and a collapsed total track length cTTL in the collapsed state, wherein S.sub.D is in the range of 7-20 mm and wherein cTTL/S.sub.D<0.6.

The present disclosure relates to a lens system and an imaging device including the lens system. The lens system may include a first lens group, a second lens group, a third lens group, a fourth lens group, and a fifth lens group in sequence from an object side to an image side along an optical axis of the lens system. At least one of the first lens group, the second lens group, the third lens group, the fourth lens group, and the fifth lens group may be adjustable along the optical axis of the lens system to adjust a focal length of the lens system. The lens system may satisfy $a\le \frac{f_2}{{\left(f_w.Math.f_t\right)}^{1/2}}\le b,c\le \frac{f_3}{{\left(f_w.Math.f_t\right)}^{1/2}}\le d,e\le \frac{f_4}{{\left(f_w.Math.f_t\right)}^{1/2}}\le f.$

An embodiment of the present invention relates to a camera module comprising: a housing; an optical system disposed in the housing; a substrate disposed under the optical system; and an imaging sensor disposed on the substrate; wherein the optical system comprises a first group lens, a second group lens, a third group lens, a fourth group lens, and a fifth group lens arranged in order, and when the third group lens moves, the effective focal length (EFL) of the optical system is changed.

An embodiment of the present invention relates to a camera module comprising: a housing; an optical system disposed in the housing; a substrate disposed under the optical system; and an imaging sensor disposed on the substrate; wherein the optical system comprises a first group lens, a second group lens, a third group lens, a fourth group lens, and a fifth group lens arranged in order, and when the third group lens moves, the effective focal length (EFL) of the optical system is changed.

The imaging lens includes, in order from a position closest to an object side to an image side: a front lens group that has a positive refractive power and is immovable during focusing; a stop that is disposed subsequent to the front lens group; a first focus lens group that has a positive refractive power; a second focus lens group that has a negative refractive power; and a final lens group that has a positive refractive power, is disposed closest to the image side, and is immovable during focusing. During focusing from an infinite distance object to a short range object, the first focus lens group and the second focus lens group move to increase a mutual distance therebetween.

A zoom lens including from object side: a positive first unit; at least one negative unit moving toward image side for zooming from wide to telephoto; and at least two positive units each moving toward object side for the zooming, in which the positive first unit includes a biconcave lens closest to object side, in which an N unit is one of the at least one negative unit and having largest amount of movement during the zooming, and P unit is one of the at least two positive units having largest amount of movement during the zooming; in which focal lengths of the first lens unit, of the zoom lens at wide end and telephoto end, a difference between distances from the N unit to image plane at telephoto end and at wide end and a distance from the P unit to image plane at telephoto end are appropriately set.