Variable magnification optical system and image pickup apparatus using the same

A variable magnification optical system comprising:

• in order from an object side,
• a first lens unit having a positive refractive power;
• a second lens unit having a negative refractive power;
• a third lens unit having a positive refractive power;
• and
• an image-side lens unit, wherein:
• the image-side lens unit includes a lens belonging to a first region and a lens belonging to a second region,
• a refractive power based on all lenses belonging to the first region is a negative refractive power, and a refractive power based on all lenses belonging to the second region is a positive refractive power,
• at a time of changing magnification,
• a distance between the lens units changes,
• the first lens unit and an aperture stop are fixed,
• the second lens unit moves so that a distance between the first lens unit and the second lens unit is widened at a telephoto end than at a wide angle end, and
• the third lens unit moves,
• the third lens unit includes a positive lens and a negative lens, and
• the following Conditional Expressions (1-1), (7), and (32) are satisfied:
• 1.52≤|fG2/fw|≤10.0 (1-1),
• 1.7≤|fG1/fG2|≤9.1 (7), and
• 0.04≤ΣG1/LTLw≤0.35 (32)
• where
• fG1 is a focal length of the first lens unit,
• fG2 is a focal length of the second lens unit,
• fw is a focal length of the variable magnification optical system at the wide angle end,
• ΣG1 is a thickness of the first lens unit, and
• LTLw is an overall length of the variable magnification optical system at the wide angle end.

A variable magnification optical system comprising:

• in order from an object side,
• a first lens unit having a positive refractive power;
• a second lens unit having a negative refractive power;
• a third lens unit having a positive refractive power;
• and
• an image-side lens unit, wherein:
• the image-side lens unit includes a lens belonging to a first region and a lens belonging to a second region,
• a refractive power based on all lenses belonging to the first region is a negative refractive power, and a refractive power based on all lenses belonging to the second region is a positive refractive power,
• at a time of changing magnification,
• a distance between the lens units changes,
• the second lens unit moves so that a distance between the first lens unit and the second lens unit is widened at a telephoto end than at a wide angle end,
• the first lens unit is fixed,
• the third lens unit moves, and
• an aperture stop moves only in one direction or is fixed,
• the first lens unit includes a negative lens and a positive lens,
• the positive lens in the first lens unit is a positive meniscus lens having a convex surface facing the object side,
• the third lens unit includes a positive lens and a negative lens, and
• the following Conditional Expression (1-3) is satisfied:
• 1.60≤|fG2/fw|≤10.0 (1-3)
• where
• fG2 is a focal length of the second lens unit, and
• fw is a focal length of the variable magnification optical system at the wide angle end.

A variable magnification optical system comprising:

• in order from an object side,
• a first lens unit having a positive refractive power;
• a second lens unit having a negative refractive power;
• a third lens unit having a positive refractive power;
• and
• an image-side lens unit, wherein:
• the image-side lens unit includes a lens belonging to a first region and a lens belonging to a second region,
• a refractive power based on all lenses belonging to the first region is a negative refractive power, and a refractive power based on all lenses belonging to the second region is a positive refractive power,
• at a time of changing magnification,
• a distance between the lens units changes,
• the second lens unit moves so that a distance between the first lens unit and the second lens unit is widened at a telephoto end than at a wide angle end,
• the first lens unit is fixed,
• the third lens unit moves, and
• an aperture stop moves only in one direction or is fixed,
• the third lens unit includes a positive lens and a negative lens, and
• the following Conditional Expression (4-1) is satisfied:
• 8.7≤fG1/fw≤50 (4-1)
• where
• fG1 is a focal length of the first lens unit, and
• fw is a focal length of the variable magnification optical system at the wide angle end.

A variable magnification optical system comprising:

• in order from an object side,
• a first lens unit having a positive refractive power;
• a second lens unit having a negative refractive power;
• a third lens unit having a positive refractive power;
• and
• an image-side lens unit, wherein:
• the image-side lens unit includes a lens belonging to a first region and a lens belonging to a second region,
• a refractive power based on all lenses belonging to the first region is a negative refractive power, and a refractive power based on all lenses belonging to the second region is a positive refractive power,
• at a time of changing magnification,
• a distance between the lens units changes,
• a distance between (i) the lenses belonging to the first region and (ii) the lenses belonging to the second region changes,
• the second lens unit moves so that a distance between the first lens unit and the second lens unit is larger at a telephoto end than at a wide angle end,
• the third lens unit moves, and
• all the lenses belonging to the second region are fixed,
• the first lens unit includes a negative lens and a positive lens,
• the positive lens in the first lens unit is a positive meniscus lens having a convex surface facing the object side,
• the following Conditional Expressions (1-1) and (2-1) are satisfied:
• 1.52≤|fG2/fw|≤10.0 (1-1), and
• 0≤ΔSS/LTLw≤0.065 (2-1)
• where
• fG2 is a focal length of the second lens unit,
• fw is a focal length of the variable magnification optical system at the wide angle end,
• ΔSS is a maximum amount of movement of an aperture stop at a time of changing magnification, and
• LTLw is an overall length of the variable magnification optical system at the wide angle end.

A variable magnification optical system comprising:

• in order from an object side,
• a first lens unit having a positive refractive power;
• a second lens unit having a negative refractive power;
• a third lens unit having a positive refractive power;
• and
• an image-side lens unit, wherein
• the image-side lens unit includes a lens belonging to a first region and a lens belonging to a second region,
• a refractive power based on all lenses belonging to the first region is a negative refractive power, and a refractive power based on all lenses belonging to the second region is a positive refractive power,
• at a time of changing magnification,
• a distance between the lens units changes,
• the second lens unit moves so that a distance between the first lens unit and the second lens unit is larger at a telephoto end than at a wide angle end,
• the third lens unit moves, and
• all the lenses belonging to the second region are fixed, and
• the following Conditional Expressions (1-2) and (3) are satisfied:
• 1.61≤|fG2/fw|≤10.0 (1-2), and
• 0.067≤fG2×PG1G2a≤0.207 (3)
• where
• fG2 is a focal length of the second lens unit,
• fw is a focal length of the variable magnification optical system at the wide angle end,
• PG1G2a is represented by the following expression:
• PG1G2a=1/RG1B−1/RG2F, where
• RG1B is a radius of curvature of a lens surface positioned closest to an image side in the first lens unit, and
• RG2F is a radius of curvature of a lens surface positioned closest to the object side in the second lens unit.

A variable magnification optical system comprising:

• in order from an object side,
• a first lens unit having a positive refractive power;
• a second lens unit having a negative refractive power;
• a third lens unit having a positive refractive power;
• and
• an image-side lens unit, wherein:
• the image-side lens unit includes a lens belonging to a first region and a lens belonging to a second region,
• a refractive power based on all lenses belonging to the first region is a negative refractive power, and a refractive power based on all lenses belonging to the second region is a positive refractive power,
• at a time of changing magnification,
• a distance between the lens units changes,
• the second lens unit moves so that a distance between the first lens unit and the second lens unit is larger at a telephoto end than at a wide angle end,
• the first lens unit is fixed, and
• the third lens unit moves,
• the first lens unit includes a negative lens and a positive lens,
• the positive lens in the first lens unit is a positive meniscus lens having a convex surface facing the object side,
• the third lens unit includes a positive lens and a negative lens, and
• the following Conditional Expressions (1-3) and (2-2) are satisfied:
• 1.60≤|fG2/fw|≤10.0 (1-3), and
• 0≤ΔSS/LTLw≤0.11 (2-2)
• where
• fG2 is a focal length of the second lens unit,
• fw is a focal length of the variable magnification optical system at the wide angle end,
• ΔSS is a maximum amount of movement of an aperture stop at a time of changing magnification, and
• LTLw is an overall length of the variable magnification optical system at the wide angle end.

A variable magnification optical system comprising:

• in order from an object side,
• a first lens unit having a positive refractive power;
• a second lens unit having a negative refractive power;
• a third lens unit having a positive refractive power;
• and
• an image-side lens unit, wherein:
• the image-side lens unit includes a lens belonging to a first region and a lens belonging to a second region,
• a refractive power based on all lenses belonging to the first region is a negative refractive power, and a refractive power based on all lenses belonging to the second region is a positive refractive power,
• at a time of changing magnification,
• a distance between the lens units changes,
• the second lens unit moves so that a distance between the first lens unit and the second lens unit is larger at a telephoto end than at a wide angle end,
• the first lens unit is fixed, and
• the third lens unit moves,
• the third lens unit includes a positive lens and a negative lens, and
• the following Conditional Expressions (2-2) and (4-1) are satisfied:
• 0≤ΔSS/LTLw≤0.11 (2-2), and
• 8.7≤fG1/fw≤50 (4-1)
• where
• ΔSS is a maximum amount of movement of an aperture stop at a time of changing magnification,
• LTLw is an overall length of the variable magnification optical system at the wide angle end,
• fG1 is a focal length of the first lens unit, and
• fw is a focal length of the variable magnification optical system at the wide angle end.

A variable magnification optical system comprising:

• in order from an object side,
• a first lens unit having a positive refractive power;
• and
• a second lens unit having a negative refractive power, wherein:
• an image-side first positive lens unit having a positive refractive power is included on an image side of the second lens unit,
• an image-side second positive lens unit having a positive refractive power is included on the image side of the image-side first positive lens unit,
• at a time of changing magnification,
• the second lens unit moves so that a distance between the first lens unit and the second lens unit is widened at a telephoto end than at a wide angle end, and
• an aperture stop moves, and
• the following Conditional Expressions (28-1), (29-1), and (32) are satisfied:
• 35.3°≤ΩHw/2≤70.0° (28-1)
• 7.0≤ft/fw≤120.0 (29-1), and
• 0.04≤ΣG1/LTLw≤0.35 (32)
• where
• ΩHw is a total angle of view in a horizontal direction at the wide angle end,
• ft is a focal length of the variable magnification optical system at the telephoto end,
• fw is a focal length of the variable magnification optical system at the wide angle end,
• ΣG1 is a thickness of the first lens unit, and
• LTLw is an overall length of the variable magnification optical system at the wide angle end.

A variable magnification optical system comprising:

• in order from an object side,
• a first lens unit having a positive refractive power;
• and
• a second lens unit having a negative refractive power, wherein:
• an image-side first positive lens unit having a positive refractive power is included on an image side of the second lens unit,
• an image-side second positive lens unit having a positive refractive power is included on the image side of the image-side first positive lens unit,
• at a time of changing magnification,
• the second lens unit moves so that a distance between the first lens unit and the second lens unit is larger at a telephoto end than at a wide angle end, and
• an aperture stop moves, and
• the following Conditional Expressions (28-2), (29-2), and (30-1) are satisfied:
• 33.4°ΩHw/2≤70.0° (28-2)
• 5.0≤ft/fw≤65.0 (29-2), and
• 0.60≤FNOw≤1.84 (30-1)
• where
• ΩHw is a total angle of view in a horizontal direction at the wide angle end,
• ft is a focal length of the variable magnification optical system at the telephoto end,
• fw is a focal length of the variable magnification optical system at the wide angle end, and
• FNOw is an F-number at the wide angle end.

A variable magnification optical system comprising:

• in order from an object side,
• a first lens unit having a positive refractive power;
• and
• a second lens unit having a negative refractive power, wherein:
• an image-side first positive lens unit having a positive refractive power is included on an image side of the second lens unit,
• an image-side second positive lens unit having a positive refractive power is included on the image side of the image-side first positive lens unit,
• at a time of changing magnification,
• the second lens unit moves so that a distance between the first lens unit and the second lens unit is larger at a telephoto end than at a wide angle end, and
• the following Conditional Expressions (29-3), (30-2), and (31) are satisfied:
• 10.0≤ft/fw≤65.0 (29-3)
• 0.60≤FNOw≤1.62 (30-2), and
• 0.70≤FNOt≤5.5 (31)
• where
• ft is a focal length of the variable magnification optical system at the telephoto end,
• fw is a focal length of the variable magnification optical system at the wide angle end,
• FNOw is an F-number at the wide angle end, and
• FNOt is an F-number at the telephoto end.

A variable magnification optical system comprising:

• in order from an object side,
• a first lens unit having a positive refractive power;
• and
• a second lens unit having a negative refractive power, wherein:
• an image-side first positive lens unit having a positive refractive power is included on an image side of the second lens unit,
• an image-side second positive lens unit having a positive refractive power is included on the image side of the image-side first positive lens unit,
• at a time of changing magnification,
• the second lens unit moves so that a distance between the first lens unit and the second lens unit is larger at a telephoto end than at a wide angle end, and
• the first lens unit is fixed, and
• the following Conditional Expressions (29-4), (33), (35), and (32-1) are satisfied:
• 10.2≤ft/fw≤120.0 (29-4),
• 0.0≤ft/fw+143.9×tan(ΩHw/2)−121.88≤110 (33),
• 2.5 mm≤Rimg≤22.0 mm (35), and
• 0.04≤ΣG1/LTLw≤0.33 (32-1)
• where
• ft is a focal length of the variable magnification optical system at the telephoto end,
• fw is a focal length of the variable magnification optical system at the wide angle end,
• ΩHw is a total angle of view in a horizontal direction at the wide angle end,
• Rimg is a radius of an image circle at an image pickup element,
• ΣG1 is a thickness of the first lens unit, and
• LTLw is an overall length of the variable magnification optical system at the wide angle end.

A variable magnification optical system comprising:

• in order from an object side,
• a first lens unit having a positive refractive power;
• and
• a second lens unit having a negative refractive power, wherein:
• an image-side first positive lens unit having a positive refractive power is included on an image side of the second lens unit,
• an image-side second positive lens unit having a positive refractive power is included on the image side of the image-side first positive lens unit,
• at a time of changing magnification,
• the second lens unit moves so that a distance between the first lens unit and the second lens unit is larger at a telephoto end than at a wide angle end, and
• the first lens unit is fixed, and
• the following Conditional Expressions (29-5), (34), (35-1), and (32-1) are satisfied:
• 6.1≤ft/fw≤120.0 (29-5)
• 0.0≤ft/fw+126.52×tan(ΩHw/2)−101.91≤120 (34)
• 3.3 mm≤Rimg≤22.0 mm (35-1)
• 0.04≤ΣG1/LTLw≤0.33 (32-1)
• where
• ft is a focal length of the variable magnification optical system at the telephoto end, fw is a focal length of the variable magnification optical system at the wide angle end,
• ΩHw is a total angle of view in a horizontal direction at the wide angle end,
• Rimg is a radius of an image circle at an image pickup element,
• ΣG1 is a thickness of the first lens unit, and
• LTLw is an overall length of the variable magnification optical system at the wide angle end.