An imaging lens consists essentially of, in order from the object side, a positive first lens group, a negative second lens group, a stop, and a positive third lens group. Focusing is effected by moving only the second lens group along the optical axis direction. Each of the first lens group and the third lens group includes at least three positive lenses and at least two negative lenses. The imaging lens satisfies the condition expression (1) below:
0.53<f2/f<0.9(1),
where f2 is a focal length of the second lens group, and f is a focal length of the entire system when the imaging lens is focused on an object at infinity.

A zoom lens includes, in order from an object side to an image side, a first lens unit having a positive refractive power, a second lens unit having a negative refractive power, a third lens unit having a positive refractive power, a rear lens group including one or more lens units, and an aperture stop. During zooming, with the first lens unit not moving, the second lens unit and at least one of the lens units of the rear lens group move. In this zoom lens, the configuration of the third lens unit and the location of the aperture stop are appropriately set.

A zoom lens includes, in order from an object side to an image side, a first lens unit having a positive refractive power, a second lens unit having a negative refractive power, a third lens unit having a positive refractive power, a rear lens group including one or more lens units, and an aperture stop. During zooming, with the first lens unit not moving, the second lens unit and at least one of the lens units of the rear lens group move. In this zoom lens, the configuration of the third lens unit and the location of the aperture stop are appropriately set.

A lens module for capturing an object light-beam from an object-side is provided. The lens module includes a first lens group, a second lens group, a third lens group, a fourth lens group and a fifth lens group sequentially-arranged from the object-side to an image-side. The five lens groups respectively have at least one lens with positive refractive-power and at least one lens with negative refractive-power. The first, third and fifth lens groups are fixed groups, while the second and fourth lens groups are movable groups. An image apparatus including the lens module is also provided.

The zoom lens according to the present invention includes in order from an object side to an image side: a first lens unit; a second lens unit; a third lens unit; an aperture stop; and a fourth lens unit; wherein a partial dispersion ratio Lm of a material of a positive lens Lm formed of a material having a highest partial dispersion ratio, which is contained in a rear group, a distance d from the aperture stop to an image plane, a distance dLm from the aperture stop to a positive lens Lm, an average value Rfp of Abbe constants of materials of positive lenses contained in a front group, an average value Rfp of partial dispersion ratios thereof, an average value Rfn of Abbe constants of materials of negative lenses contained in the front group, and an average value Rfn of partial dispersion ratios thereof are each appropriately set.

A variable magnification optical system includes, in order from the object side: a positive first lens group, which is fixed when changing magnification; a negative second lens group that moves from the object side to the image side when changing magnification from the wide angle end to the telephoto end; and a rearward lens group having a positive refractive power throughout the entire variable magnification range that includes at least one lens group that moves when changing magnification. The first lens group includes, in order from the object side, a positive first lens group front group, a positive first lens group middle group, and a first lens group rear group constituted by a negative lens. The first lens group front group and first lens group middle group include cemented lenses formed by cementing a negative lens and a positive lens, provided in this order from the object side, together.

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/f.sub.w<1.0, wherein f1 is the effective focal length of the first lens group, and f.sub.w is the effective focal length of the zoom lens at a wide end.

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/f.sub.w<1.0, wherein f1 is the effective focal length of the first lens group, and f.sub.w is the effective focal length of the zoom lens at a wide end.

Embodiments of this application disclose a zoom lens, a camera module, and a mobile terminal. The zoom lens includes a first lens group, a second lens group, a third lens group, and a fourth lens group that are arranged along an object side to an image side. The first lens group is a fixed lens group with positive focal power, the second lens group is a zoom lens group with negative focal power, the third lens group is a compensative lens group with positive focal power, and the fourth lens group is a fixed lens group with positive focal power. In a zooming process of the zoom lens from a short-focal end to a long-focal end, the second lens group moves towards the image side along an optical axis, and the third lens group moves towards the object side along the optical axis.

Embodiments of this application disclose a zoom lens, a camera module, and a mobile terminal. The zoom lens includes a first lens group, a second lens group, a third lens group, and a fourth lens group that are arranged along an object side to an image side. The first lens group is a fixed lens group with positive focal power, the second lens group is a zoom lens group with negative focal power, the third lens group is a compensative lens group with positive focal power, and the fourth lens group is a fixed lens group with positive focal power. In a zooming process of the zoom lens from a short-focal end to a long-focal end, the second lens group moves towards the image side along an optical axis, and the third lens group moves towards the object side along the optical axis.