Small three-unit zoom lens

A zoom lens system which comprises, in order from the object side,

• a first lens unit having a positive refractive power;
• a second lens unit having a negative refractive power;
• and
• a third lens unit consisting of a front sub-unit having a positive refractive power and a rear sub-unit including a negative meniscus lens convex on the image side and having a negative refractive power, said third lens unit having a positive refractive power as a whole;
• said first lens unit remaining fixed, and
• said second and third lens units being moved along the optical axis such that a maximum amount of movement of said second lens unit is larger than a maximum amount of movement of said third lens unit, whereby zooming is carried out;
• wherein all lenses in said first lens unit are in the form of meniscus lenses convex on the object side.

A zoom lens system which comprises, in order from the object side,

• a first lens unit having a positive refractive power;
• a second lens unit having a negative refractive power;
• and
• a third lens unit consisting of a front sub-unit having a positive refractive power and a rear sub-unit including a negative meniscus lens convex on the image side and having a negative refractive power, said third lens unit having a positive refractive power as a whole;
• said first lens unit remaining fixed, and
• said second and third lens units being moved along the optical axis such that a maximum amount of movement of said second lens unit is larger than a maximum amount of movement of said third lens unit, whereby zooming is carried out;
• wherein all negative lens units in said second lens unit are in the form of negative meniscus lenses convex on the object side.

A zoom lens system which comprises, in order from the object side,

• a first lens unit having a positive refractive power;
• a second lens unit having a negative refractive power;
• and
• a third lens unit consisting of a front sub-unit having a positive refractive power and a rear sub-unit including a negative meniscus lens convex on the image side and having a negative refractive power, said third lens unit having a positive refractive power as a whole;
• said first lens unit remaining fixed, and
• said second and third lens units being moved along the optical axis such that a maximum amount of movement of said second lens unit is larger than a maximum amount of movement of said third lens unit, whereby zooming is carried out;
• wherein said first lens unit includes at least one aspherical lens.

A zoom lens system which comprises, in order from the object side,

• a first lens unit having a positive refractive power;
• a second lens unit having a negative refractive power;
• and
• a third lens unit consisting of a front sub-unit having a positive refractive power and a rear sub-unit including a negative meniscus lens convex on the image side and having a negative refractive power, said third lens unit having a positive refractive power as a whole;
• said first lens unit remaining fixed, and
• said second and third lens units being moved along the optical axis such that a maximum amount of movement of said second lens unit is larger than a maximum amount of movement of said third lens unit, whereby zooming is carried out;
• wherein said second lens unit includes at least one aspherical lens.

A zoom lens system which comprises, in order from the object side,

• a first lens unit having a positive refractive power;
• a second lens unit having a negative refractive power;
• and
• a third lens unit consisting of a front sub-unit having a positive refractive power and a rear sub-unit including a negative meniscus lens convex on the image side and having a negative refractive power, said third lens unit having a positive refractive power as a whole;
• said first lens unit remaining fixed, and
• said second and third lens units being moved along the optical axis such that a maximum amount of movement of said second lens unit is larger than a maximum amount of movement of said third lens unit, whereby zooming is carried out;
• wherein said third lens unit includes at least one aspherical lens.

A zoom lens system which comprises, in order from the object side,

• a first lens unit having a positive refractive power;
• a second lens unit having a negative refractive power;
• and
• a third lens unit consisting of a front sub-unit having a positive refractive power and a rear sub-unit including a negative meniscus lens convex on the image side and having a negative refractive power, said third lens unit having a positive refractive power as a whole;
• said first lens unit remaining fixed, and
• said second and third lens units being moved along the optical axis such that a maximum amount of movement of said second lens unit is larger than a maximum amount of movement of said third lens unit, whereby zooming is carried out;
• wherein said zoom lens system satisfies the following condition (4):
• -1<.beta..sub.3 <0 (4)
• where
• .beta..sub.3 is the transverse magnification of said third lens unit.