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US 2002/0001145 A1Published application
Real image mode finder optical system
AssigneeOlympus Optical Co., Ltd.
InventorAkiyoshi Tochigi
Life of this patent
Estimating the term…
Abstract
A real image mode finder optical system is constructed to be independent of a photographing optical system and includes, in order from the object side, an objective optical system with a positive refracting power, a field frame located in the proximity of the imaging position of the objective optical system, and an eyepiece optical system with a positive refracting power. The real image mode finder optical system has an image erecting means, and the focal length of the objective optical system can be made shorter than that of the eyepiece optical system. In this case, the real image mode finder optical system satisfies the following condition: 0.52<mh/fe<1 where mh is the maximum width of the field frame and fe is the focal length of the eyepiece optical system.
Claims56
A real image mode finder optical system constructed to be independent of a photographing optical system, comprising, in order from an object side:
- an objective optical system with a positive refracting power;
- a field frame located in the proximity of an imaging position of said objective optical system;
- and
- an eyepiece optical system with a positive refracting power,
- wherein said real image mode finder optical system includes image erecting means, and a focal length of said objective optical system can be made shorter than a focal length of said eyepiece optical system, said real image mode finder optical system satisfying the following condition:
- 0.52<mh/fe<1
- where mh is a maximum width of said field frame and fe is a focal length of said eye-piece optical system.
4 more elements
A real image mode finder optical system comprising, in order from an object side:
- an objective optical system with a positive refracting power;
- a field frame located in the proximity of an imaging position of said objective optical system;
- and
- an eyepiece optical system with a positive refracting power,
- wherein said real image mode finder optical system includes image erecting means, and said objective optical system includes three of reflecting surfaces of said image erecting means and said eyepiece optical system includes one of reflecting surfaces of said image erecting means so that an image is erected through four reflecting surfaces comprised of three reflecting surfaces of said objective optical system and one reflecting surface of said eyepiece optical system, and
- wherein a focal length of said objective optical system is variable, and when a magnification of said finder optical system is changed, at least two lens units are moved along different paths and a focal length of said objective optical system at a wide-angle position thereof is shorter than a focal length of said eyepiece optical system, said real image mode finder optical system satisfying the following condition:
- 0.52<mh/fe<1
- where mh is a maximum width of said field frame and fe is a focal length of said eye-piece optical system.
5 more elements
A real image mode finder optical system comprising, in order from an object side:
- an objective optical system with a positive refracting power;
- a field frame located in the proximity of an imaging position of said objective optical system;
- and
- an eyepiece optical system with a positive refracting power,
- wherein said real image mode finder optical system includes image erecting means, and said objective optical system includes three of reflecting surfaces of said image erecting means and said eyepiece optical system includes one of reflecting surfaces of said image erecting means so that an image is erected through four reflecting surfaces comprised of three reflecting surfaces of said objective optical system and one reflecting surface of said eyepiece optical system,
- wherein a focal length of said objective optical system is variable, and when a magnification of said finder optical system is changed, at least two lens units are moved along different paths and a focal length of said objective optical system at a wide-angle position thereof is shorter than a focal length of said eyepiece optical system, and
- wherein said image erecting means including said three reflecting surfaces of said objective optical system is constructed with two prisms so that each of said prisms has at least one reflecting surface and one of an entrance surface and an exit surface of each prism is configured as a curved surface with finite curvature.
4 more elements
A real image mode finder optical system comprising, in order from an object side:
- an objective optical system with a positive refracting power;
- a field frame located in the proximity of an imaging position of said objective optical system;
- and
- an eyepiece optical system with a positive refracting power,
- wherein said objective optical system has image erecting means including four reflecting surfaces, and
- wherein a focal length of said objective optical system is variable, and when a magnification of said finder optical system is changed, at least two lens units are moved along different paths and a focal length of said objective optical system at a wide-angle position thereof is shorter than a focal length of said eyepiece optical system, said real image mode finder optical system satisfying the following condition:
- 0.52<mh/fe<1
- where mh is a maximum width of said field frame and fe is a focal length of said eye-piece optical system.
5 more elements
A real image mode finder optical system comprising, in order from an object side:
- an objective optical system with a positive refracting power;
- a field frame located in the proximity of an imaging position of said objective optical system;
- and
- an eyepiece optical system with a positive refracting power,
- wherein said objective optical system has image erecting means including four reflecting surfaces, and
- wherein a focal length of said objective optical system is variable, and when a magnification of said finder optical system is changed, at least two lens units are moved along different paths and a focal length of said objective optical system at a wide-angle position thereof is shorter than a focal length of said eyepiece optical system.
3 more elements
A photographing apparatus provided with a real image mode finder optical system comprising, in order from an object side:
- an objective optical system with a positive refracting power;
- a field frame located in the proximity of an imaging position of said objective optical system;
- and
- an eyepiece optical system with a positive refracting power,
- wherein said real image mode finder optical system includes image erecting means, and a focal length of said objective optical system can be made shorter than a focal length of said eyepiece optical system, said real image mode finder optical system satisfying the following condition:
- 0.52<mh/fe<1
- where mh is a maximum width of said field frame and fe is a focal length of said eye-piece optical system.
4 more elements
A real image mode finder optical system constructed to be independent of a photographing optical system, comprising, in order from an object side:
- an objective optical system with a positive refracting power;
- a field frame located in the proximity of an imaging position of said objective optical system;
- and
- an eyepiece optical system with a positive refracting power,
- wherein said real image mode finder optical system includes an image erecting means and
- wherein said objective optical system is capable of having a focal length shorter than a focal length of said eyepiece optical system, and said eyepiece optical system has at least one lens element so that a most observer's pupil-side lens element satisfies the following condition:
- ν>70
- where ν is an Abbe's number of said most observer's pupil-side lens element.
5 more elements
A real image mode finder optical system constructed to be independent of a photographing optical system, comprising, in order from an object side:
- an objective optical system with a positive refracting power;
- a field frame located in the proximity of an imaging position of said objective optical system;
- and
- an eyepiece optical system with a positive refracting power,
- wherein said real image mode finder optical system includes an image erecting means and
- wherein said objective optical system is capable of having a focal length shorter than a focal length of said eyepiece optical system, and said eyepiece optical system has at least one lens element to satisfy the following conditions:
- 0.52<mh/fe<1 ν>70
- where mh is a maximum width of said field frame, fe is a focal length of said eyepiece optical system, and ν is an Abbe's number of a most observer's pupil-side lens element.
5 more elements
A real image mode finder optical system constructed to be independent of a photographing optical system, comprising, in order from an object side:
- an objective optical system with a positive refracting power;
- a field frame located in the proximity of an imaging position of said objective optical system;
- and
- an eyepiece optical system with a positive refracting power,
- wherein said real image mode finder optical system includes an image erecting means and
- wherein said objective optical system is capable of having a focal length shorter than a focal length of said eyepiece optical system, and said eyepiece optical system has a cemented lens component including a positive lens element and a negative lens element at a most observer's pupil-side position.
3 more elements
A real image mode finder optical system constructed to be independent of a photographing optical system, comprising, in order from an object side:
- an objective optical system with a positive refracting power;
- a field frame located in the proximity of an imaging position of said objective optical system;
- and
- an eyepiece optical system with a positive refracting power,
- wherein said real image mode finder optical system includes an image erecting means and
- wherein said objective optical system is capable of having a focal length shorter than a focal length of said eyepiece optical system, and said eyepiece optical system has a cemented lens component including a positive lens element and a negative lens element at a most observer's pupil-side position to satisfy the following condition:
- 0.52<mh/fe<1
- where mh is a maximum width of said field frame and fe is a focal length of said eye-piece optical system.
5 more elements
A photographing apparatus provided with a real image mode finder optical system constructed to be independent of a photographing optical system, comprising, in order from an object side:
- an objective optical system with a positive refracting power;
- a field frame located in the proximity of an imaging position of said objective optical system;
- and
- an eyepiece optical system with a positive refracting power,
- wherein said real image mode finder optical system includes an image erecting means and
- wherein said objective optical system is capable of having a focal length shorter than a focal length of said eyepiece optical system, and said eyepiece optical system has at least one lens element so that a most observer's pupil-side lens element satisfies the following condition:
- ν>70
- where ν is an Abbe's number of said most observer's pupil-side lens element.
5 more elements
A real image mode finder optical system comprising, in order from an object side;
- an objective optical system with a positive refracting power;
- a field frame located in the proximity of an imaging position of said objective optical system;
- and
- an eyepiece optical system with a positive refracting power,
- wherein said real image mode finder optical system includes image erecting means, and
- wherein said objective optical system includes, in order from said object side, a first unit with a negative refracting power, a second unit with a positive refracting power, a third unit with a negative refracting power, and a fourth unit with a positive refracting power so that a magnification of said finder optical system is changed, ranging from a wide-angle position to a telephoto position, by simply moving said second unit toward said object side and said third unit toward said eyepiece optical system to satisfy the following condition:
- 12.0 mm<fe<18.0 mm
- where fe is a focal length of said eyepiece optical system.
5 more elements
A real image mode finder optical system comprising, in order from an object side;
- an objective optical system with a positive refracting power;
- a field frame located in the proximity of an imaging position of said objective optical system;
- and
- an eyepiece optical system with a positive refracting power,
- wherein said real image mode finder optical system includes image erecting means, and
- wherein said objective optical system includes, in order from said object side, a first unit with a negative refracting power, a second unit with a positive refracting power, a third unit with a negative refracting power, and a fourth unit with a positive refracting power so that a magnification of said finder optical system is changed, ranging from a wide-angle position to a telephoto position, by simply moving said second unit toward said object side and said third unit toward said eyepiece optical system to satisfy the following condition:
- 0.52<mh/fe<1
- where mh is a maximum width of said field frame and fe is a focal length of said eye-piece optical system.
5 more elements
A real image mode finder optical system comprising, in order from an object side;
- an objective optical system with a positive refracting power;
- a field frame located in the proximity of an imaging position of said objective optical system;
- and
- an eyepiece optical system with a positive refracting power,
- wherein said real image mode finder optical system includes image erecting means, and
- wherein said objective optical system is capable of having a focal length shorter than a focal length of said eyepiece optical system, and said eyepiece optical system includes, in order from said object side, a prism unit with a positive refracting power and a lens unit with a positive refracting power so that a most field-frame-side surface of said prism unit with a positive refracting power has a positive refracting power and is configured as an aspherical surface with a negative refracting power on a periphery thereof.
3 more elements
A photographing apparatus provided with a real image mode finder optical system comprising, in order from an object side:
- an objective optical system with a positive refracting power;
- a field frame located in the proximity of an imaging position of said objective optical system;
- and
- an eyepiece optical system with a positive refracting power,
- wherein said real image mode finder optical system includes image erecting means, and
- wherein said objective optical system includes, in order from said object side, a first unit with a negative refracting power, a second unit with a positive refracting power, a third unit with a negative refracting power, and a fourth unit with a positive refracting power so that a magnification of said finder optical system is changed, ranging from a wide-angle position to a telephoto position, by simply moving said second unit toward said object side and said third unit toward said eyepiece optical system to satisfy the following condition:
- 12.0 mm<fe<18.0 mm
- where fe is a focal length of said eyepiece optical system.
5 more elements
A real image mode finder optical system comprising, in order from an object side:
- an objective optical system which has a positive refracting power and changes a magnification of said finder optical system;
- a field frame located in the proximity of an imaging position of said objective optical system;
- and
- an eyepiece optical system with a positive refracting power,
- wherein said real image mode finder optical system has image erecting means, and
- wherein said objective optical system includes, in order from said object side, a front unit with a negative refracting power and a rear unit with a positive refracting power,
- said front unit being constructed with a plurality of lens units so that a magnification of said finder optical system is changed, ranging from a wide-angle position to a telephoto position, by moving at least two of said plurality of lens units and
- said rear unit being constructed with a plurality of prism units with positive refracting powers so that at least one of surfaces opposite to one another, of said plurality of prism units is configured to be convex.
5 more elements
A real image mode finder optical system comprising, in order from an object side:
- an objective optical system which has a positive refracting power and changes a magnification of said finder optical system;
- a field frame located in the proximity of an imaging position of said objective optical system;
- and
- an eyepiece optical system with a positive refracting power,
- wherein said real image mode finder optical system has image erecting means, and
- wherein said objective optical system includes, in order from said object side, a first unit with a negative refracting power, a second unit with a positive refracting power, a third unit with a negative refracting power, and a fourth unit with a positive refracting power,
- said fourth unit being comprised of a fourth front sub-unit and a fourth rear sub-unit,
- a magnification of said finder optical system being changed, ranging from a wide-angle position to a telephoto position, by moving said second unit and said third unit,
- each of said first unit, said second unit, and said third unit being constructed with a lens, and
- each of said fourth front sub-unit and said fourth rear sub-unit being constructed with a prism so that at least one of surfaces opposite to each other, of said fourth front sub-unit and said fourth rear sub-unit is configured to be convex.
7 more elements
A real image mode finder optical system according to claim 58, wherein said fourth front sub-unit includes a single prism and has one reflecting surface.
A photographing apparatus provided with a real image mode finder optical system comprising, in order from an object side:
- an objective optical system which has a positive refracting power and changes a magnification of said finder optical system;
- a field frame located in the proximity of an imaging position of said objective optical system;
- and
- an eyepiece optical system with a positive refracting power,
- wherein said real image mode finder optical system has image erecting means, and
- wherein said objective optical system includes, in order from said object side, a front unit with a negative refracting power and a rear unit with a positive refracting power, said front unit being constructed with a plurality of lens units so that a magnification of said finder optical system is changed, ranging from a wide-angle position to a telephoto position, by moving at least two of said plurality of lens units and said rear unit being constructed with a plurality of prism units with positive refracting powers SO that at least one of surfaces opposite to one another, of said plurality of prism units is configured to be convex.
3 more elements
A real image mode finder optical system comprising, in order from an object side:
- an objective optical system which has a positive refracting power and changes a magnification of said finder optical system;
- a field frame located in the proximity of an imaging position of said objective optical system;
- and
- an eyepiece optical system with a positive refracting power,
- wherein said real image mode finder optical system has image erecting means,
- wherein said objective optical system includes, in order from said object side, a first unit with a negative refracting power, a second unit with a positive refracting power, a third unit with a negative refracting power, and a fourth unit with a positive refracting power so that a magnification of said finder optical system is changed, ranging from a wide-angle position to a telephoto position, by simply moving said second unit toward said object side and said third unit toward an eyepiece side, and
- wherein a combined focal length of said first unit, said second unit, and said third unit is negative, and when said magnification is changed over a range from said wide-angle position to said telephoto position, a combined imaging magnification of said second unit and said third unit is 1×.
4 more elements
A photographing apparatus provided with a real image mode finder optical system comprising, in order from an object side:
- an objective optical system which has a positive refracting power and changes a magnification of said finder optical system;
- a field frame located in the proximity of an imaging position of said objective optical system;
- and
- an eyepiece optical system with a positive refracting power,
- wherein said real image mode finder optical system has image erecting means,
- wherein said objective optical system includes, in order from said object side, a first unit with a negative refracting power, a second unit with a positive refracting power, a third unit with a negative refracting power, and a fourth unit with a positive refracting power so that a magnification of said finder optical system is changed, ranging from a wide-angle position to a telephoto position, by simply moving said second unit toward said object side and said third unit toward an eyepiece side, and
- wherein a combined focal length of said first unit, said second unit, and said third unit is negative, and when said magnification is changed over a range from said wide-angle position to said telephoto position, a combined imaging magnification of said second unit and said third unit is 1×.
4 more elements
Dependencies are inferred from the claim text.