Variable magnification optical system having image stabilizing function

A variable magnification optical system having an image stabilizing function, comprising, in order from an object side:

• a first lens unit of positive refractive power, said first lens unit remaining stationary during variation of magnification;
• a second lens unit of negative refractive power, said second lens unit moving along an optical axis during variation of magnification;
• a third lens unit of positive refractive power;
• and
• a fourth lens unit of positive refractive power, said fourth lens unit moving along the optical axis during variation of magnification;
• wherein said third lens unit as a whole is movable so as to have a component in a direction perpendicular to the optical axis to stabilize the image, and
• wherein said third lens unit has two positive lenses and one negative lens, with one of the two positive lenses being located nearest to an object, and
• wherein said third lens has one of said two positive lenses, said one negative lens and the other of said two positive lenses arranged in the order from the object side to the image side.

A variable magnification optical system having an image stabilizing function, comprising, in order from an object side:

• a first lens unit of positive refractive power, said first lens unit remaining stationary during variation of magnification;
• a second lens unit of negative refractive power, said second lens unit moving along an optical axis during variation of magnification;
• a third lens unit of positive refractive power;
• and
• a fourth lens unit consisting of one lens member, wherein said one lens member has a positive refractive power, said fourth lens unit moving along the optical axis during variation of magnification, and
• wherein said third lens unit as a whole is movable so as to have a component in a direction perpendicular to the optical axis to stabilize the image.

A variable magnification optical system having an image stabilizing function, comprising:

• a fixed first lens unit of positive refractive power,
• a second lens unit of negative refractive power,
• a third lens unit of positive refractive power, said third lens unit comprises, in order from the object side to the image side, a positive first lens, a negative second lens and a positive third lens, and
• a fourth lens unit of positive refractive power,
• wherein said second lens unit and said fourth unit move during zooming, and
• wherein at least a part of said third lens unit is movable so as to have a component in a direction vertical to the optical axis to stabilize the image.

A variable magnification optical system having an image stabilizing function, comprising:

• a fixed first lens unit of positive refractive power,
• a second lens unit of negative refractive power,
• a third lens unit of positive refractive power, said third lens unit having two positive lenses and one negative lens, and
• a fourth lens unit of positive refractive power, satisfying the following condition:
• 1.0<|f3N/f3|<1.6
• where f3N and f3 are focal lengths of said negative lens and said third lens unit, respectively,
• wherein said second lens unit and said fourth lens unit move during zooming, and
• wherein at least a part of said third lens unit is movable so as to have a component in a direction vertical to the optical axis to stabilize the image.

A variable magnification optical system having an image stabilizing function, comprising:

• a fixed first lens unit of positive refractive power,
• a second lens unit of negative refractive power,
• a third lens unit of positive refractive power, said third lens unit having two positive lenses and one negative lens, and
• a fourth lens unit of positive refractive power,
• wherein said second lens unit and said fourth lens unit move during zooming, and
• wherein at least a part of said third lens unit is movable so as to have a component in a direction vertical to the optical axis to stabilize the image, and
• wherein said third lens unit has an aspheric surface formed on said negative lens or on one of said two positive lenses disposed on the image side of said negative lens.

A variable magnification optical system having an image stabilizing function, comprising:

• a fixed first lens unit of positive refractive power,
• a second lens unit of negative refractive power,
• a third lens unit of positive refractive power, said third lens unit having two positive lenses and one negative lens, and
• a fourth lens unit of positive refractive power,
• wherein said second lens unit and said fourth lens unit move during zooming, and
• wherein at least a part of said third lens unit is movable so as to have a component in a direction vertical to the optical axis to stabilize the image, and wherein said third lens unit comprises a positive first lens having a strong convex surface facing the object side, a negative second lens of meniscus form concave toward the image side, and a positive third lens of meniscus form convex toward the object side.

A variable magnification optical system having an image stabilizing function, comprising:

• a fixed first lens unit of positive refractive power,
• a second lens unit of negative refractive power,
• a third lens unit of positive refractive power, said third lens unit having two positive lenses and one negative lens, and
• a fourth lens unit of positive refractive power, satisfying the following condition:
• 0.23<|f2/{square root over (fW·fT)}|<0.35
• where f2 is a focal length of said second lens unit, and fW and fT are focal length at a wide-angle end and a telephoto end of the entire optical system, respectively wherein said second lens and said fourth lens unit move during zooming,
• wherein at least a part of said third lens unit is movable so as to have a component in a direction vertical to the optical axis to stabilize the image, and said variable magnification optical system has as a lens unit only said first lens unit, said second lens unit, said third lens unit and said fourth lens unit.

A variable magnification optical system having an image stabilizing function, comprising:

• a fixed first lens unit of positive refractive power,
• a second lens unit of negative refractive power,
• a third lens unit of positive refractive power, said third lens unit having two positive lenses and one negative lens, and
• a fourth lens unit of positive refractive power, satisfying the following condition:
• 3.5 × 10 - 3 < DM ⁢ ( 1 - β ⁢ ⁢ 3 ⁢ t ) ⁢ β4t fT < 5.2 × 10 - 2
• where fT is the focal length at the telephoto end, Dm is a maximum movement of said third lens unit in stabilizing an image, and β3t and β4t are paraxial lateral magnification at a telephoto end of said third lens unit and said fourth lens unit, respectively,
• wherein said second lens unit and said fourth lens unit move during zooming, and
• wherein said third lens unit is moved so as to have a component in a direction vertical to the optical axis to stabilize the image, and said variable magnification optical system has as a lens unit only said first lens unit, said second lens unit, said third lens unit and said fourth lens unit.