Variable magnification optical system, optical apparatus, imaging apparatus and method for manufacturing variable magnification optical system

A method for manufacturing a variable magnification optical system, comprising steps of:

• arranging a first lens group disposed at a most object side and having positive refractive power, a second lens group disposed at an image side of the first lens group and having negative refractive power, and a rear group disposed at an image side of the second lens group and having positive refractive power such that, upon varying magnification from an wide angle end state to a telephoto end state, the first lens group is moved toward the object side, a distance between the first lens group and the second lens group and a distance between the second lens group and the rear group are varied;
• the rear group being composed of a focusing group that is moved upon focusing, an A group having positive refractive power, and a B group satisfying the following conditional expression with respect to the A group and having negative refractive power:
• 0.11<Dvrw/TLw<0.25
• where Dvrw denotes a distance from the A group to the B group in the wide angle end state, and
• TLw denotes a whole length of the variable magnification optical system in the wide angle end state.

A method for manufacturing a variable magnification optical system, comprising:

• arranging a first lens group disposed at a most object side and having positive refractive power, a second lens group disposed at an image side of the first lens group and having negative refractive power and a rear group disposed at an image side of the second lens group and having positive refractive power such that, upon varying magnification from a wide angle end state to a telephoto end state, the first lens group is moved toward the object side, a distance between the first lens group and the second lens group and a distance between the second lens group and the rear group are varied,
• the first lens group comprising at least one negative lens that satisfies the following conditional expression:
• nN<1.70
• where nN denotes refractive index of the negative lens in the first lens group at d line (wavelength 587.6 nm), and the rear group comprising a focusing group that is moved upon focusing, an A group having positive refractive power, and a B group satisfying the following conditional expression with respect to the A group and having negative refractive power:
• 0.11<Dvrw/TLw<0.25
• where Dvrw denotes a distance from the A group to the B group in the wide angle end state, and
• TLw denotes a whole length of the variable magnification optical system in the wide angle end state.

A method for manufacturing a variable magnification optical system, comprising a step of

• arranging a first lens group disposed at a most object side and having positive refractive power, a second lens group disposed at an image side of the first lens group and having negative refractive power, and a rear group disposed at an image side of the second lens group and having positive refractive power such that, upon varying magnification from a wide angle end state to a telephoto end state, the first lens group is moved toward the object side, a distance between the first lens group and the second lens group and a distance between the second lens group and the rear group are varied,
• the rear group comprising a focusing group moving upon focusing, an A group having positive refractive power and a B group satisfying the following conditional expression with respect to the A group and having negative refractive power:
• 0.11<Dvrw/TLw<0.25
• where Dvrw denotes a distance from the A group to the B group in the wide angle end state, and
• TLw denotes a whole length of the variable magnification optical system in the wide angle end state;
• and
• an aperture stop disposed at an image side of the focusing group.

A variable magnification optical system comprising a first lens group disposed at a most object side and having positive refractive power, a second lens group disposed at an image side of the first lens group and having negative refractive power, and a rear group disposed at an image side of the second lens group and having positive refractive power;

• upon varying magnification from an wide angle end state to a telephoto end state, the first lens group being moved toward the object side, a distance between the first lens group and the second lens group and a distance between the second lens group and the rear group being varied;
• the rear group comprising a focusing group;
• the first lens group comprising at least one negative lens that satisfies the following conditional expression:
• nN<1.70
• where nN denotes refractive index at d-line (wavelength 587.6 nm) of the negative lens in the first lens group.

A variable magnification optical system comprising a first lens group disposed at a most object side and having positive refractive power, a second lens group disposed at an image side of the first lens group and having negative refractive power, and a rear group disposed at an image side of the second lens group and having positive refractive power;

• upon varying magnification from an wide angle end state to a telephoto end state, the first lens group being moved toward the object side, a distance between the first lens group and the second lens group and a distance between the second lens group and the rear group being varied;
• the rear group comprises a focusing group that is moved upon focusing;
• and
• an aperture stop being disposed at an image side of the focusing group.