Zoom lens and electronic imaging device having the same

A zoom lens comprising, in order from an object side:

• a first lens unit having a reflective optical component with a reflecting surface for bending an optical path, as a most object-side lens unit remaining fixed when a magnification is changed;
• a second lens unit with negative refracting power, constructed as a first moving lens unit moved along an optical axis when the magnification is changed;
• a third lens unit with positive refracting power, constructed as a second moving lens unit moved along the optical axis when the magnification is changed;
• and
• a most image-side lens unit located at a most image-side position,
• the second lens unit being moved back and forth along the optical axis on an image side to follow a convex path, when the magnification is changed, extending from a wide-angle position to a telephoto position.

An electronic imaging device comprising:

• a zoom lens;
• and
• an electronic image sensor located on an image side of the zoom lens,
• the zoom lens comprising:
• a most object-side lens unit located at a most object-side position, remaining fixed on an optical axis when a magnification of the zoom lens is changed and a focusing operation is performed;
• a most image-side lens unit located at a most image-side position, remaining fixed on the optical axis when the focusing operation is performed;
• and
• moving lens units lying between the most object-side lens unit and the most image-side lens unit, moved along the optical axis when the magnification is changed,
• the most object-side lens unit comprising, in order from an object side, a negative lens component, a reflective optical component having a reflecting surface for bending an optical path, and a positive lens component, and
• the most image-side lens unit having at least one aspherical surface.

An electronic imaging device comprising:

• a zoom lens;
• and
• an electronic image sensor located on an image side of the zoom lens,
• the zoom lens comprising:
• a most object-side lens unit located at a most object-side position, remaining fixed on an optical axis when a magnification of the zoom lens is changed and a focusing operation is performed;
• a most image-side lens unit located at a most image-side position, remaining fixed on the optical axis when the focusing operation is performed;
• and
• moving lens units lying between the most object-side lens unit and the most image-side lens unit, moved along the optical axis when the magnification is changed,
• the most object-side lens unit comprising, in order from an object side, a negative lens component, a reflective optical component having a reflecting surface for bending an optical path, and a positive lens component, and
• the most image-side lens unit having at least one aspherical surface,
• wherein the most object-side lens unit comprises, in order from the object side, the negative lens component, the reflective optical component having the reflecting surface for bending the optical path, and the positive lens component, and the zoom lens satisfies the following conditions:
• 1.0<−f11/{square root}{square root over ((fw·fT))}<2.5 1.4<f12/{square root}{square root over ((fw·fT))}<3.2
• where f11 is a focal length of the negative lens component in the most object-side lens unit, f12 is a focal length of the positive lens component in the most object-side lens unit, fw is a focal length of an entire system at a wide-angle position of the zoom lens, fT is a focal length of an entire system at a telephoto position of the zoom lens, and
• wherein the zoom lens further satisfies the following condition:
• 0.7<d/L<2.0
• where d is an air-equivalent length measured along the optical axis from an image-side vertex of the negative lens component to an object-side vertex of the positive lens component in the most object-side lens unit, and L is a diagonal length of an effective imaging area of the electronic image sensor.

An electronic imaging device comprising:

• a zoom lens;
• and
• an electronic image sensor located on an image side of the zoom lens, the zoom lens comprising, in order from an object side:
• a first lens unit having a reflective optical component with a reflecting surface for bending an optical path, constructed as a most object-side lens unit remaining fixed when a magnification is changed;
• a second lens unit with negative refracting power, constructed as a first moving lens unit moved along an optical axis when the magnification is changed;
• a third lens unit with positive refracting power, constructed as a second moving lens unit moved along the optical axis when the magnification is changed;
• and
• a most image-side lens unit located at a most image-side position,
• the second lens unit being moved back and forth along the optical axis on an image side to follow a convex path, when the magnification is changed, extending from a wide-angle position to a telephoto position,
• wherein the third lens unit comprises two positive lens elements and one negative lens element and the negative lens element is cemented to at least one of the positive lens elements, and
• wherein the third lens unit comprises, in order from the object side, a single positive lens and a cemented lens component with a positive lens element and a negative lens element,
• the zoom lens satisfying the following conditions:
• −0.3<L/CC2<1.0 15<vCP−vCN
• where L is a diagonal length (mm) of an image sensor used, RC2 is a radius of curvature, on the optical axis, of an interface of the cemented lens component in the third lens unit, vCP is an Abbe's number of a medium of the positive lens element of the cemented lens component in the third lens unit, and vCN is an Abbe's number of a medium of the negative lens element of the cemented lens component in the third lens unit.

An electronic imaging device comprising:

• a zoom lens;
• and
• an electronic image sensor located on an image side of the zoom lens,
• the zoom lens comprising, in order from an object side:
• a first lens unit having a reflective optical component with a reflecting surface for bending an optical path, constructed as a most object-side lens unit remaining fixed when a magnification is changed;
• a second lens unit with negative refracting power, constructed as a first moving lens unit moved along an optical axis when the magnification is changed;
• a third lens unit with positive refracting power, constructed as a second moving lens unit moved along the optical axis when the magnification is changed;
• and
• a most image-side lens unit located at a most image-side position,
• the second lens unit being moved back and forth along the optical axis on an image side to follow a convex path, when the magnification is changed, extending from a wide-angle position to a telephoto position,
• wherein the third lens unit comprises two positive lens elements and one negative lens element and the negative lens element is cemented to at least one of the positive lens elements, and
• wherein the third lens unit comprises, in order from the object side, a cemented lens component with a positive lens element and a negative lens element, and a single positive lens,
• the zoom lens satisfying the following conditions:
• −0.1<L/RC2<0.8 15<vCP−vCN
• where L is a diagonal length (mm) of an image sensor used, RC2 is a radius of curvature, on the optical axis, of an interface of the cemented lens component in the third lens unit, vCP is an Abbe's number of a medium of the positive lens element of the cemented lens component in the third lens unit, and vCN is an Abbe's number of a medium of the negative lens element of the cemented lens component in the third lens unit.

A zoom lens comprising:

• a most object-side lens unit located at a most object-side position, remaining fixed when a magnification of the zoom lens is changed;
• a most image-side lens unit located at a most image-side position, remaining fixed when the magnification is changed;
• and
• a first moving lens unit with negative refracting power and a second moving lens unit with positive refracting power, lying between the most object-side lens unit and the most image-side lens unit, moved along an optical axis when the magnification is changed,
• the most object-side lens unit comprising a reflective optical component having a reflecting surface for bending an optical path.

A zoom lens comprising:

• a most object-side lens unit located at a most object-side position, remaining fixed on an optical axis when a magnification of the zoom lens;
• a first moving lens unit with negative refracting power, lying across air spacing from the most object-side lens unit, moved along the optical axis when the magnification is changed;
• a second moving lens unit with positive refracting power, moved toward an object side so that when the magnification is changed, extending from a wide-angle position to a telephoto position, spacing between the first moving lens unit and the second moving lens unit is narrowed, and
• a most image-side lens unit that spacing between the second moving lens unit and the most image-side lens unit is varied when the magnification is changed,
• the most object-side lens unit comprising, in order from the object side, a negative lens element, a refractive optical element having a reflecting surface for bending an optical path, and a positive lens element,
• the first moving lens unit comprising a negative lens element and a positive lens element,
• the second moving lens unit comprising three lens elements,
• the most image-side lens unit comprising a single lens element or a cemented lens component, and
• a stop being provided and moved together with the second moving lens unit when the magnification is changed.

A zoom lens comprising:

• a most object-side lens unit located at a most object-side position, remaining fixed when a magnification of the zoom lens is changed;
• a most image-side lens unit located at a most image-side position;
• and
• a first moving lens unit and a second moving lens unit, lying between the most object-side lens unit and the most image-side lens unit, moved along an optical axis when the magnification is changed,
• the most object-side lens unit comprising, in order from an object side, a negative lens component, a front surface mirror having a reflecting surface for bending an optical path, and a positive lens component, and
• the most image-side lens unit having at least one aspherical surface.

A zoom lens comprising, in order from an object side:

• a first lens unit including a positive lens component, constructed as a most object-side lens unit remaining fixed when a magnification is changed;
• a second lens unit with negative refracting power, constructed as a first moving lens unit moved along an optical axis when the magnification is changed;
• a third lens unit with positive refracting power, constructed as a second moving lens unit moved along the optical axis when the magnification is changed;
• and
• a most image-side lens unit located at a most image-side position,
• the first lens unit comprising, in order from the object side, a negative lens component and a front surface mirror having a reflecting surface for bending an optical path, and
• the reflecting surface being deformable.

An electronic imaging device comprising:

• a zoom lens;
• and
• an electronic image sensor located on an image side of the zoom lens,
• the zoom lens comprising:
• a most object-side lens unit located at a most object-side position, remaining fixed when a magnification of the zoom lens is changed;
• a most image-side lens unit located at a most image-side position;
• and
• a first moving lens unit and a second moving lens unit, lying between the most object-side lens unit and the most image-side lens unit, moved along an optical axis when the magnification is changed,
• the most object-side lens unit comprising, in order from an object side, a negative lens component, a front surface mirror having a reflecting surface for bending an optical path, and a positive lens component, and
• the most image-side lens unit having at least one aspherical surface.