Zoom lens and optical apparatus having the same

A zoom lens, comprising, in order from an object side to an image side:

• a first lens unit of negative optical power, said first lens unit including a negative meniscus lens having a concave surface facing the image side and a positive meniscus lens having a convex surface facing the object side;
• a second lens unit of positive optical power, said second lens unit including a negative lens of bi-concave form, a positive lens disposed on the object side of the negative lens of bi-concave form and having a convex surface facing the object side, and a cemented lens of positive optical power as a whole disposed on the image side of the negative lens of bi-concave form;
• and
• a third lens unit of positive optical power,
• wherein a separation between said first lens unit and said second lens unit and a separation between said second lens unit and said third lens unit are varied to effect variation of magnification.

A zoom lens, comprising, in order from an object side to an image side:

• a first lens unit of negative optical power, said first lens unit including a negative meniscus lens having a concave surface facing the image side and a positive meniscus lens having a convex surface facing the object side;
• a second lens unit of positive optical power, said second lens unit including, in order from the object side to the image side, one or two positive lenses, a negative lens of bi-concave form, and a cemented lens of positive optical power as a whole;
• and
• a third lens unit of positive optical power,
• wherein a separation between said first lens unit and said second lens unit and a separation between said second lens unit and said third lens unit are varied to effect variation of magnification, and
• wherein said zoom lens satisfies the following conditions:
• 0.5<fc/f2<2.0 0.5<(Ra+Rb)/(Ra−Rb)<2.5 0.3<|fn|/f2<2.0 0.5<(Rd+Rc)/(Rd−Rc)<2.5
• where fc is a focal length of the cemented lens in said second lens unit, fn is a focal length of the negative lens in said second lens unit, f2 is a focal length of said second lens unit, Ra is a radius of curvature of a surface on the object side of the cemented lens in said second lens unit, Rb is a radius of curvature of a surface on the image side of the negative lens in said second lens unit, and Rc and Rd are radii of curvature of lens surfaces on the object side and the image side, respectively, of the positive lens disposed on the most object side of said second lens unit.

A zoom lens, comprising, in order from an object side to an image side:

• a first lens unit of negative optical power, said first lens unit including a negative lens and a positive lens;
• a second lens unit of positive optical power, said second lens unit consisting of a cemented lens and one positive lens;
• and
• a third lens unit of positive optical power, said third lens unit including a positive lens,
• wherein a separation between said first lens unit and said second lens unit and a separation between said second lens unit and said third lens unit are varied to effect variation of magnification.

A zoom lens, comprising, in order from an object side to an image side:

• a first lens unit of negative optical power;
• a second lens unit of positive optical power;
• and
• a third lens unit of positive optical power, said third lens unit consisting of one or two lenses including a positive lens,
• wherein a separation between said first lens unit and said second lens unit and a separation between said second lens unit and said third lens unit are varied to effect variation of magnification, and
• wherein said zoom lens satisfies the following conditions:
• ndp3<1.5 νdp3>70.0
• where ndp3 and νdp3 are a refractive index and Abbe number, respectively, of material of the positive lens in said third lens unit.

A zoom lens, comprising, in order from an object side to an image side:

• a first lens unit of negative optical power;
• a second lens unit of positive optical power;
• and
• a third lens unit of positive optical power,
• wherein a separation between said first lens unit and said second lens unit and a separation between said second lens unit and said third lens unit are varied to effect variation of magnification, and
• wherein, during the variation of magnification from a wide-angle end to a telephoto end with an infinitely distant object focused on, said third lens unit moves monotonically toward the image side or moves with a locus convex toward the image side, and said zoom lens satisfies the following condition:
• 0.08<M3/fw<0.4
• where M3 is an amount of movement of said third lens unit toward the image side during the variation of magnification from the wide-angle end to the telephoto end with an infinitely distant object focused on, and fw is a focal length of said zoom lens at the wide-angle end.

A zoom lens, comprising, in order from an object side to an image side:

• a first lens unit of negative optical power, said first lens unit consisting of, in order from the object side to the image side, a negative lens and a positive lens;
• a second lens unit of positive optical power;
• and
• a third lens unit of positive optical power,
• wherein a separation between said first lens unit and said second lens unit and a separation between said second lens unit and said third lens unit are varied to effect variation of magnification,
• wherein, with an infinitely distant object focused on, said third lens unit is located nearer to the image side at a telephoto end than at a wide-angle end, and
• wherein said zoom lens satisfies the following condition:
• 0.7<|f1/ft|<1.0
• where f1 is a focal length of said first lens unit, and ft is a focal length of said zoom lens at the telephoto end.

A zoom lens, comprising, in order from an object side to an image side:

• a first lens unit of negative optical power, said first lens unit consisting of, in order from the object side to the image side, a negative lens and a positive lens;
• a second lens unit of positive optical power;
• and
• a third lens unit of positive optical power, focusing being effected by moving said third lens unit,
• wherein a separation between said first lens unit and said second lens unit and a separation between said second lens unit and said third lens unit are varied to effect variation of magnification, and
• wherein, during the variation of magnification from a wide-angle end to a telephoto end with an infinitely distant object focused on, said third lens unit moves monotonically toward the image side or moves with a locus convex toward the image side, and said zoom lens satisfies the following conditions:
• 0.08<M3/fw<0.4 0.7<|f1/ft|<1.0 1.45<f3/ft<2.0 0.63<f2/ft<0.8
• where M3 is an amount of movement of said third lens unit toward the image side during the variation of magnification from the wide-angle end to the telephoto end with an infinitely distant object focused on, fw and ft are focal lengths of said zoom lens at the wide-angle end and the telephoto end, respectively, and f1, f2 and f3 are focal lengths of said first lens unit, said second lens unit and said third lens unit, respectively.