A zoom lens is constituted by, in order from the object side to the image side: a positive first group which is fixed when changing magnification, a negative second lens group which moves when changing magnification, a negative third lens group which moves when changing magnification, and a positive fourth lens group which is fixed when changing magnification. The first lens group is constituted by a 1a lens of a negative meniscus shape, a positive 1b lens, and a positive 1c lens. The second lens group is constituted by a negative 2a lens, a biconcave 2b lens, a positive 2c lens, and a negative 2d lens. The third lens group is constituted by a negative 3a lens and a positive 3b lens. The fourth lens group includes a 4a lens, an aperture stop, and a positive 4b lens, which are consecutively provided from the most object side thereof.

A zoom lens unit includes, in order from an object side to an image side, a first lens group having positive refractive power and a focus function, a second lens group having negative refractive power, which moves when changing a magnification, a third lens group which moves when changing a magnification, and a fourth lens group having positive refractive power, which is fixed when changing a magnification, wherein the following condition (1) is fulfilled:

|M.sub.2W.Math.M.sub.3W.Math.M.sub.4W|<0.14 (1) where M.sub.2W represents an imaging magnification of the second lens group at a wide-angle end, M.sub.3W represents an imaging magnification.the third lens group at the wide-angle end, and M.sub.4W represents an imaging magnification of the fourth lens group at the wide-angle end.

A zoom lens including, in order from an object side: a positive first lens unit not moving for zooming; a negative second lens unit moving during zooming; a negative third lens unit moving during zooming; and a fourth lens unit not moving for zooming and including an aperture stop, the fourth lens unit including first and second sub-lens units arranged on object side and image plane side of the aperture stop, respectively, in which a relationship between a maximum height of an axial ray from an optical axis in the first sub-lens unit when focusing at infinity at a wide angle end, and a maximum height of an axial ray at the aperture stop when focusing at infinity at the wide angle end and of full open aperture, and a lateral magnification of the fourth lens unit when focusing at infinity at the wide angle end are appropriately set.

Provided is a zoom lens, including, in order from an object side to an image side: a positive first lens unit that does not move for zooming; a negative second lens unit that moves during zooming; and a positive N-th lens unit that does not move for zooming and is arranged closest to the image side. Among lenses constructing the second lens unit, two lenses closest to the image side are a positive lens and a negative lens, and partial dispersion ratios for g-line and F-line and Abbe numbers for a d-line of the positive and negative lenses, and an average value of refractive indices of all the lenses of the second lens unit are appropriately set.

A zoom lens unit includes, in order from an object side to an image side, a first lens group having positive refractive power and a focus function, a second lens group having negative refractive power, which moves when changing a magnification, a third lens group which moves when changing a magnification, and a fourth lens group having positive refractive power, which is fixed when changing a magnification, wherein the following condition (1) is fulfilled:
|M.sub.2W.Math.M.sub.3W.Math.M.sub.4W|<0.14(1)
where M.sub.2W represents an imaging magnification of the second lens group at a wide-angle end, M.sub.3W represents an imaging magnification of the third lens group at the wide-angle end, and M.sub.4W represents an imaging magnification of the fourth lens group at the wide-angle end.

A zoom lens includes, in the order starting from the object side to the side of an image plane, a first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having negative refractive power, and a fourth lens group having positive refractive power. The fourth lens group includes, in the order starting from the side closest to the image plane to the object side, a first positive lens, a first negative lens, a second negative lens and a second positive lens. The fourth lens group G4 has a configuration that satisfies the following conditional expression (1) when d.sub.P1 represents an Abbe number of the first positive lens L46 and d.sub.N1 represents an Abbe number of the first negative lens L45:
40<d.sub.P1d.sub.N1<0(1).

A zoom lens includes: a first lens group having a positive refractive power which is fixed while changing magnification; two or more movable lens groups that move independently from each other while changing magnification; and a final lens group having a positive refractive power which is fixed while changing magnification, provided in this order from an object side. The zoom lens satisfying Conditional Formula (1) below:
1.30<h/(Yimg.Math.tan )<2.37(1).

The art has, disposed in order from an object, a first lens group (G1) having positive refractive power, a second lens group (G2) having negative refractive power, a third lens group (G3) having negative refractive power, and a fourth lens group (G4) having positive refractive power, in which zooming is made by varying an air distance between the first lens group (G1) and the second lens group (G2), and the following conditional expression (1) is satisfied:

0.60<f4/fw<1.15(1) where f4 denotes a focal distance of the fourth lens group (G4), and fw denotes a focal distance of a zoom lens in a wide-angle end state upon focusing on infinity.

A zoom lens is constituted by, in order from the object side to the image side: a positive first group which is fixed when changing magnification, a negative second lens group which moves when changing magnification, a negative third lens group which moves when changing magnification, and a positive fourth lens group which is fixed when changing magnification. The first lens group is constituted by a 1a lens of a negative meniscus shape, a positive 1b lens, and a positive 1c lens. The second lens group is constituted by a negative 2a lens, a biconcave 2b lens, a positive 2c lens, and a negative 2d lens. The third lens group is constituted by a negative 3a lens and a positive 3b lens. The fourth lens group includes a 4a lens, an aperture stop, and a positive 4b lens, which are consecutively provided from the most object side thereof.

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.