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US 6,185,049 B2Granted
Zoom lens system
AssigneeMinolta Co., Ltd.
InventorsMamoru Terada, Takashi Okada, Yasushi Yamamoto, Kazuhiko Ishimaru
Life of this patent
Estimating the term…
Abstract
A zoom lens system has, from the object side, a first lens unit having a positive optical power, a second lens unit having a positive optical power and provided at the image side of the first lens unit with a first variable air space between the first and second lens units, and a third lens unit having a negative optical power and provided at the image side of the second lens unit with a second variable air space between the second and third lens units, wherein a zooming operation is performed by varying the first and second air spaces, and wherein the zooming fulfills the predetermined condition with respect to a lateral magnification of the third lens unit in a shortest focal length condition.
Claims36
A zoom lens system comprising, from the object side:
- a first lens unit having a positive optical power;
- a second lens unit having a positive optical power and provided at the image side of the first lens unit with a first variable air space between the first and second lens units, and
- a third lens unit having a negative optical power and provided at the image side of the second lens unit with a second variable air space between the second and third lens units,
- wherein a zooming operation is performed by varying the first and second air spaces, and
- wherein the zooming fulfills the following conditions:
- 1.7<β3W<2.0, and
- 0.40<LBW/Y′<0.71
- where
- β3W represents a lateral magnification of the third lens unit in a shortest focal length condition,
- LBW represents a lens back length in the shortest focal length condition (the lens back length is defined as a distance between a summit of a most image side surface of the zoom lens system and an image plane), and
- Y′ represents a maximum image height.
8 more elements
A zoom lens system comprising, from the object side:
- a first lens unit having a positive optical power;
- a second lens unit having a positive optical power and provided at the image side of the first lens unit with a first variable air space between the first and second lens units, and
- a third lens unit having a negative optical power and provided at the image side of the second lens unit with a second variable air space between the second and third lens units,
- wherein a zooming operation is performed by varying the first and second air spaces, and
- wherein the zooming fulfills the following conditions:
- 1.00<TLW/Y′<1.75
- −0.8−f3/fW<−0.4
- where
- TLW represents a total length in a shortest focal length condition (the total length is defined as a distance between a summit of a most object side surface of the zoom lens system and an image plane),
- Y′ represents a maximum image height,
- f3 represents a focal length of the third lens unit, and
- fW represents an entire focal length in the shortest focal length condition.
9 more elements
A zoom lens system comprising, from the object side:
- a first lens unit having a positive optical power;
- a second lens unit having a positive optical power and provided at the image side of the first lens unit with a first variable air space between the first and second lens units, and
- a third lens unit having a negative optical power and provided at the image side of the second lens unit with a second variable air space between the second and third lens units,
- wherein a zooming operation is performed by varying the first and second air spaces, and
- wherein the zooming fulfills the following conditions:
- 1.00<TLW/Y′<1.75
- 1.8<fT/fW<5.0
- where
- TLW represents a total length in a shortest focal length condition (the total length is defined as a distance between a summit of a most object side surface of the zoom lens system and an image plane),
- Y′ represents a maximum image height,
- fT represents an entire focal length in a longest focal length condition, and
- fW represents an entire focal length in the shortest focal length condition.
9 more elements
A zoom lens system comprising, from the object side:
- a first lens unit having a positive optical power and including a first resin lens element;
- a second lens unit having a positive optical power and provided at the image side of the first lens unit with a first variable air space between the first and second lens units;
- and
- a third lens unit having a negative optical power and provided at the image side of the second lens unit with a second variable air space between the second and third lens units, the third lens unit including a second resin lens element,
- wherein a zooming operation is performed by varying the first and second air spaces and wherein the zoom lens system fulfills the following condition:
- −2<f1p/f3p<−1
- where
- f1p represents a focal length of the first resin lens element, and
- f3p represents a focal length of the second resin lens element.
6 more elements
A zoom lens system comprising, from the object side:
- a first lens unit having a positive optical power and including a resin lens element;
- a second lens unit having a positive optical power and provided at the image side of the first lens unit with a first variable air space between the first and second lens units, and
- a third lens unit having a negative optical power and provided at the image side of the second lens unit with a second variable air space between the second and third lens units,
- wherein a zooming operation is performed by varying the first and second air spaces, and
- wherein the zoom lens system fulfills the following condition:
- 1.00<TLW/Y′<1.75
- where
- TLW represents a total length in a shortest focal length condition (the total length is defined as a distance between a summit of a most object side surface of the zoom lens system and an image plane), and
- Y′ represents a maximum image height.
6 more elements
A zoom lens system comprising, from the object side:
- a first lens unit having a positive optical power;
- a second lens unit having a positive optical power and provided at the image side of the first lens unit with a first variable air space between the first and second lens units, and
- a third lens unit having a negative optical power and provided at the image side of the second lens unit with a second variable air space between the second and third lens units, the third lens unit including a resin lens element.
- wherein a zooming operation is performed by varying the first and second air spaces, and
- wherein the zoom lens system fulfills the following condition:
- 1.00<TLW/Y′<1.75
- where
- TLW represents a total length in a shortest focal length condition (the total length is defined as a distance between a summit of a most object side surface of the zoom lens system and an image plane), and
- Y′ represents a maximum image height.
6 more elements
A zoom lens system having at least three lens units including at least one positive lens unit and at least one negative lens unit,
- wherein a zooming operation is performed by varying air spaces between the lens units, and
- wherein at least either the positive lens unit or the e negative lens unit consists of a single lens element,
- wherein the following conditions are fulfilled:
- −0.0020<Lt<0.0020
- 0.02<|Lgp|<0.20
- 0.02<|Lgn|<0.20
- 0.60<|Lgp/Lgn|<1.40
- where
- Lt represents an axial chromatic aberration coefficient of the entire zoom lens system in a longest focal length condition with an entire focal length of the zoom lens system as a normalized unit,
- Lgp represents an axial chromatic aberration coefficient of the positive lens unit with the entire focal length of the zoom lens system as a normalized unit, and
- Lgn represents an axial chromatic aberration coefficient of the negative lens unit with the entire focal length of the zoom lens system as a normalized unit.
8 more elements
A zoom lens system having at least three lens units including at least one positive lens unit and at least one negative lens unit,
- wherein a zooming operation is performed by varying air spaces between the lens units, and
- wherein at least either the positive lens unit or the negative lens unit consists of a single lens element,
- wherein the following conditions are fulfilled:
- 0.50<fp/fW<1.00
- −0.70<fn/fW<−0.40
- 0.60<|Lgp/Lgn|<1.40
- where
- fp represents a focal length of the positive lens unit,
- fn represents a focal length of the negative lens unit,
- fW represents an entire focal length in a shortest focal length condition,
- Lgp represents an axial chromatic aberration coefficient of the positive lens unit with the entire focal length of the zoom lens system as a normalized unit, and
- Lgn represents an axial chromatic aberration coefficient of the negative lens unit with the entire focal length of the zoom lens system as a normalized unit.
9 more elements
Dependencies are inferred from the claim text.