Zoom lens system

A zoom lens system comprising:

• a plurality of lens units;
• wherein a lens unit which is disposed on an image side among said plurality of lens units has a negative refractive power, said lens unit which has the negative refractive power consists of a first subunit having a negative refractive power,
• wherein said first subunit comprises a cemented lens component consisting of a negative lens element and a positive lens element,
• wherein said second subunit consists only of a negative lens component,
• wherein said lens unit disposed on the image side comprises at least one aspherical surface,
• wherein said zoom lens system satisfies the following condition (1):
• -0. 6<f.sub.GR /f.sub.GF <-0.17 (1)
• wherein the reference symbol f.sub.GF represents a focal length of said first subunit and the reference symbol f.sub.GR designates a focal length of said second subunit,
• wherein said aspherical surface has such a shape as to weaken a negative refractive power as portions of the aspherical surface are farther from an optical axis thereof, and
• wherein said zoom lens system satisfies the following condition (2):
• 0.1<f.sub.GN /f.sub.LF <0.9 (2)
• wherein the reference symbol f.sub.GN represents a focal length of said lens unit disposed on the image side and the reference symbol f.sub.LF designates a focal length of the negative lens element disposed in said first subunit.

A zoom lens system comprising:

• a plurality of lens units;
• wherein a lens unit which is disposed on an image side among said plurality of lens units has a negative refractive power, said lens unit which has the negative refractive power consists of a first subunit having a negative refractive power,
• wherein said first subunit comprises a cemented lens component consisting of a negative lens element and a positive lens element,
• wherein said second subunit consists only of a negative lens component,
• wherein said lens unit disposed on the image side comprises at least one aspherical surface,
• wherein said zoom lens system satisfies the following condition (1):
• -0.6<f.sub.GR /f.sub.GF <-0.17 (1)
• wherein the reference symbol f.sub.GF represents a focal length of said first subunit and the reference symbol f.sub.GR designates a focal length of said second subunit, and
• wherein a lens unit having a positive refractive power is disposed on the object side of said lens unit disposed on the image side and an airspace reserved between these two lens units is varied for zooming the lens system.

A zoom lens system comprising:

• a plurality of lens units;
• wherein a lens unit which is disposed on an image side among said plurality of lens units has a negative refractive power, said lens unit which has the negative refractive power consists of a first subunit having a negative refractive power,
• wherein said first subunit comprises a cemented lens component consisting of a negative lens element and a positive lens element,
• wherein said second subunit consists only of a negative lens component,
• wherein said lens unit disposed on the image side comprises at least one aspherical surface,
• wherein said zoom lens system satisfies the following condition (1):
• -0. 6<f.sub.GR /f.sub.GF <-0.17 (1)
• wherein the reference symbol f.sub.GF represents a focal length of said first subunit and the reference symbol f.sub.GR designates a focal length of said second subunit, and
• wherein two lens units having positive refractive powers are disposed on the object side of said lens unit disposed on the image side and airspaces reserved among the lens units adjacent to one another are varied for zooming the lens system.

A zoom lens system comprising:

• a plurality of lens units;
• wherein a lens unit which is disposed on an image side among said plurality of lens units has a negative refractive power, said lens unit which has the negative refractive power consists of a first subunit having a negative refractive power,
• wherein said first subunit comprises a cemented lens component consisting of a negative lens element and a positive lens element,
• wherein said second subunit consists only of a negative lens component,
• wherein said lens unit disposed on the image side comprises at least one aspherical surface,
• wherein said zoom lens system satisfies the following condition (1):
• -0. 6<f.sub.GR /f.sub.GF <-0.17 (1)
• wherein the reference symbol f.sub.GF represents a focal length of said first subunit and the reference symbol f.sub.GR designates a focal length of said second subunit, and
• wherein the cemented lens component disposed in said first subunit has a meniscus shape.

A zoom lens system comprising:

• a plurality of lens units;
• wherein a lens unit which is disposed on an image side among said plurality of lens units has a negative refractive power, said lens unit which has the negative refractive power consists of a first subunit having a negative refractive power,
• wherein said first subunit comprises a cemented lens component consisting of a negative lens element and a positive lens element,
• wherein said second subunit consists only of a negative lens component,
• wherein said lens unit disposed on the image side comprises at least one aspherical surface,
• wherein said zoom lens system satisfies the following condition (1):
• -0. 6<f.sub.GR /f.sub.GF <-0.17 (1)
• wherein the reference symbol f.sub.GF represents a focal length of said first subunit and the reference symbol f.sub.GR designates a focal length of said second subunit, and
• wherein the negative lens element disposed in said first subunit is a lens element which has an aspherical surface and is made of a synthetic resin material.