Zoom lens system consisting of two lens units

A zoom lens system consisting, in order from the object side, of a first lens unit having a positive refractive power and a second lens unit having a negative refractive power, and configured to change a magnification from a wide position to a teleposition by moving the lens units toward the object side so as to narrow an airspace reserved between the first lens unit and the second lens unit, wherein said first lens unit consists of a first negative subunit and a second positive subunit which are arranged in order from the object side, respectively, before and after a widest airspace reserved in the first lens unit, wherein the first negative subunit of said first lens unit comprises, in order from the object side, a biconcave lens component having radius of curvature on the image side which is smaller than that on the object side and a negative meniscus lens component having a convex surface on the object side, wherein the second positive subunit of said first lens unit consists of a positive lens component, wherein said second lens unit comprises, in order from the object side, a positive lens component and a negative lens component, and wherein said zoom lens system satisfies the following conditions (1), (2) and (3)

• 0.2<|fG11/D|<1.8 (1)
• νL4<50 (2)
• 50<νL5<70 (3)
• wherein the reference symbol fG11 represents a focal length of the first negative subunit G1l of the first lens unit G1, the reference symbol D designates a diagonal length of an image surface, the reference symbol νL4 denotes an Abbe's number of the positive lens component L4 of the second lens unit G2 and the reference symbol νL5 represents an Abbe's number of the negative lens component L5 of the second lens unit G2.

A zoom lens system consisting, in order from the object side, of a first lens unit having a positive refractive power, and a second lens unit having a negative refractive power, and configured to change a magnification from a wide position to a teleposition by moving the lens units toward the object side so as to narrow an airspace reserved between the first lens unit and the second lens unit, wherein said first lens unit consists, in order from the object side, of a first negative subunit and a second positive subunit wherein the first negative subunit of said first lens unit comprises, in order from the object side, a biconcave lens component having radius of curvature on the image side which is smaller than that on the object side, and a negative meniscus lens component which uses at least an aspherical surface, is made of a plastic material and has a convex surface on the object side, wherein the second positive subunit of said first lens unit comprises a positive lens component, wherein said second lens unit consists, in order from the object side, of a positive lens component which uses at least an aspherical surface and is made of a plastic material, and a negative lens component, and wherein said zoom lens system satisfies the following conditions (1) and (3):

• 0.2<|fG11/D|<1.8 (1)
• 50<νL5<70 (3)
• wherein the reference symbol fG11 represents a focal length of the first negative subunit G11 of the first lens unit G1, the reference symbol D designates a diagonal length or an image surface and the reference symbol νL5 represents an Abbe's number of the negative lens component L5 of the second lens unit G2.

A zoom lens system consisting, in order from the object side, of a first lens unit having a positive refractive power and a second lens unit having a negative refractive power, and configured to change a magnification from a wide position to a teleposition by moving the lens units toward the object side so as to narrow an airspace reserved therebetween the first lens unit and the second lens unit, wherein said first lens unit consists, in order from the object side, of a first negative subunit and a second positive subunit with a wide airspace reserved therebetween, wherein the first negative subunit of said first lens unit comprises, in order from the object side, a biconcave lens component having radius of curvature on the image side which is shorter than that on the object side, and a negative meniscus lens component which uses at least an aspherical surface, is made of a plastic material, and has a convex surface on the object side, wherein the second positive subunit of said first lens unit consists of a positive lens component, wherein said second lens unit comprises, in order from the object side, a positive lens component which uses at least an aspherical surface and is made of a plastic material, and a negative lens component, and wherein said zoom lens system satisfies the following conditions (1) and (3):

• 0.2<|fG11/D|<1.8 (1)
• 50<νL5<70 (3)
• wherein the reference symbol fG11 represents a focal length of the first negative subunit G11 of the first lens unit G1, the reference symbol D designates a diagonal length of an image surface, and the reference symbol νL5 represents an Abbe's number of the negative lens component L5 of the second lens unit G2.

A zoom lens system consisting, in order from the object side, of a first lens unit having a positive refractive power, and a second lens unit having a negative refractive power, and configured to change a magnification from a wide position to a teleposition by moving the lens units toward the object side so as to narrow an airspace reserved between the first lens unit and the second lens unit, wherein said first lens unit consists, in order from the object side, of a first negative subunit and a second positive subunit, wherein the first negative subunit disposed in said first lens unit consists of a negative lens element having a radius of curvature on the image side which is smaller than that on the object side, wherein the second positive subunit disposed in said first lens unit consists of a negative lens element and a positive lens element, wherein said second lens unit comprise at least a positive lens element and a negative lens element, and wherein said zoom lens system satisfies the following conditions (5) and (6):

• 0.2<|fIN/D|<2.1 (5)
• 5<νd(R)−νd(F)<20 (6)
• wherein the reference symbol fIN represents a focal length of the respective negative lens elements disposed in the first lens unit, the reference symbol D designates a diagonal length of an image surface, the reference symbol νd(R) denotes an Abbe's number of the negative lens element disposed on the image side, and the reference symbol νd(F) represents an Abbe's number of the negative lens element disposed on the object side.

A zoom lens system consisting, in order from the object side, of a first lens unit having a positive refractive power, and a second lens unit having a negative refractive power, and configured to change a magnification from a wide position to a teleposition by moving the lens units so as to narrow an airspace reserved between the first lens unit and the second lens unit, wherein said first lens unit consists, in order from the object aide, of a first negative subunit and a second positive subunit, wherein the first negative subunit disposed in said first lens unit consists of a negative lens element having a radius of curvature on the image side which is smaller than that on the object side, wherein the second positive subunit disposed in said first lens unit comprising at least a negative lens element and at least a positive lens element, wherein said second lens unit comprises at least a positive lens element and at least negative lens element, and wherein said zoom lens system satisfies the following conditions (5) and (6) and (7):

• 0.2<|fIN/D|<2.1 (5)
• 5<νd(R)−νd(F)<20 (6)
• −5.0<(R2+R1)/(R2−R1)<−0.9 (7)
• wherein the reference symbol fIN represents a focal length of the respective negative lens elements disposed in the first lens unit, the reference symbol D designates a diagonal length of the photographing screen, the reference symbol νd(R) denotes an Abbe's number of the negative lens element disposed on the image side, the reference symbol v, (F) represents an Abbe's number of the negative lens element disposed on the object side, the reference symbol R1 designates a radius of curvature on an object side surface of the negative lens element of the first negative subunit disposed in the first lens unit and the reference symbol R2 denotes a radius of curvature on an image side surface of the negative lens element of the first negative subunit disposed in the first lens unit.

A zoom lens system consisting, in order from the object side, of a first lens unit having a positive refractive power, and a second lens unit having a negative refractive power, and configured to change a magnification from a wide position to a teleposition by moving the lens units so as to narrow an airspace reserved between the first lens unit and the second lens unit, wherein said first lens unit consists, in order from the object side, of a first negative subunit and a second positive subunit, wherein the first negative subunit disposed in said first lens unit consists, in order from the object side, of a negative lens element having a radius of curvature on the object side which is smaller than that on the image side, and a meniscus lens element having a convex surface on the object side, wherein the second positive subunit disposed in said first lens unit comprises at least a negative lens element and at least a positive lens element, wherein said second lens unit comprises at least a positive lens element and at least a negative lens element, and wherein said zoom lens system satisfies the following conditions (8) and (6):

• 0.2<|fIF/D|<2.1 (8)
• 5<νd(R)−νd(F)<20 (6)
• wherein the reference symbol fIF represents a focal length of the first negative subunit elements disposed in said first lens unit, the reference symbol D designates a diagonal length of an image surface, the reference symbol νd(R) denotes an Abbe's number of the negative lens element disposed on the image side, and the reference symbol νd(F) represents an Abbe's number of the negative lens element disposed on the object side.