Zoom lens system, imaging device and camera

An imaging device capable of outputting an optical image of an object as an electric image signal, comprising:

• a zoom lens system that forms the optical image of the object;
• and
• an image sensor that converts the optical image formed by the zoom lens system into the electric image signal, wherein
• in the zoom lens system,
• the zoom lens system, in order from an object side to an image side, comprises a first lens unit having positive optical power, a second lens unit having negative optical power, a third lens unit having positive optical power, and a fourth lens unit having positive optical power, wherein
• the first lens unit is composed of three or fewer lens elements, wherein
• the second lens unit is composed of three lens elements, wherein
• in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit, the second lens unit, the third lens unit and the fourth lens unit are moved individually along an optical axis such that air spaces between the individual lens units should vary, so that variable magnification is achieved, and wherein
• the following conditions (5), (6), (a-2) and (b) are satisfied:
• tan 2ωW×m2W≦−1.78 (5)
• tan 2ωW×|fG2|/fG1≧1.25 (6)
• ωW≧37 (a-2)
• fT/fW≧10 (b)
• where,
• m2W is a lateral magnification of the second lens unit at a wide-angle limit in an infinity in-focus condition,
• fG1 is a composite focal length of the first lens unit,
• fG2 is a composite focal length of the second lens unit,
• ωW is a half view angle (°) at a wide-angle limit,
• fT is a focal length of the entire system at a telephoto limit, and
• fW is a focal length of the entire system at a wide-angle limit.

A camera for converting an optical image of an object into an electric image signal and then performing at least one of displaying and storing of the converted image signal, comprising

• an imaging device including a zoom lens system that forms the optical image of the object and an image sensor that converts the optical image formed by the zoom lens system into the electric image signal, wherein
• in the zoom lens system,
• the zoom lens system, in order from an object side to an image side, comprises a first lens unit having positive optical power, a second lens unit having negative optical power, a third lens unit having positive optical power, and a fourth lens unit having positive optical power, wherein
• the first lens unit is composed of three or fewer lens elements, wherein
• the second lens unit is composed of three lens elements, wherein
• in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit, the second lens unit, the third lens unit and the fourth lens unit are moved individually along an optical axis such that air spaces between the individual lens units should vary, so that variable magnification is achieved, and wherein
• the following conditions (5), (6), (a-2) and (b) are satisfied:
• tan 2ωW×m2W≧−1.78 (5)
• tan 2ωW×|fG2|/fG1≧1.25 (6)
• ωW≧37 (a-2)
• fT/fW≧10 (b)
• where,
• M2W is a lateral magnification of the second lens unit at a wide-angle limit in an infinity in-focus condition,
• fG1 is a composite focal length of the first lens unit,
• fG2 is a composite focal length of the second lens unit,
• ωW is a half view angle (°) at a wide-angle limit,
• fT is a focal length of the entire system at a telephoto limit, and
• fW is a focal length of the entire system at a wide-angle limit.

A zoom lens system, in order from an object side to an image side, comprising a first lens unit having positive optical power, a second lens unit having negative optical power, a third lens unit having positive optical power, and a fourth lens unit having positive optical power, wherein

• the first lens unit is composed of three or fewer lens elements, wherein
• the second lens unit is composed of three lens elements, wherein
• in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit, the second lens unit, the third lens unit and the fourth lens unit are moved individually along an optical axis such that air spaces between the individual lens units should vary, so that variable magnification is achieved, and wherein
• the following conditions (7), (8), (a-2) and (b) are satisfied:
• −3.12≦TG1/fW≦−2.36 (7)
• 1.26≦TG2/fW≦1.78 (8)
• ωW≧37 (a-2)
• fT/fW≧10 (b)
• where,
• TG1 is an amount of axial movement of the first lens unit from the object side to the image side in zooming from a wide-angle limit to a telephoto limit at the time of image taking,
• TG2 is an amount of axial movement of the second lens unit from the object side to the image side in zooming from a wide-angle limit to a telephoto limit at the time of image taking,
• ωW is a half view angle (°) at a wide-angle limit,
• fT is a focal length of the entire system at a telephoto limit, and
• fW is a focal length of the entire system at a wide-angle limit.

An imaging device capable of outputting an optical image of an object as an electric image signal, comprising:

• a zoom lens system that forms the optical image of the object;
• and
• an image sensor that converts the optical image formed by the zoom lens system into the electric image signal, wherein
• in the zoom lens system,
• the zoom lens system, in order from an object side to an image side, comprises a first lens unit having positive optical power, a second lens unit having negative optical power, a third lens unit having positive optical power, and a fourth lens unit having positive optical power, wherein
• the first lens unit is composed of three or fewer lens elements, wherein
• the second lens unit is composed of three lens elements, wherein
• in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit, the second lens unit, the third lens unit and the fourth lens unit are moved individually along an optical axis such that air spaces between the individual lens units should vary, so that variable magnification is achieved, and wherein
• the following conditions (7), (8), (a-2) and (b) are satisfied:
• −3.12≦TG1/fW≦−2.36 (7)
• 1.26≦TG2/fW≦1.78 (8)
• ωW≧37 (a-2)
• fT/fW≧10 (b)
• where,
• TG1 is an amount of axial movement of the first lens unit from the object side to the image side in zooming from a wide-angle limit to a telephoto limit at the time of image taking,
• TG2 is an amount of axial movement of the second lens unit from the object side to the image side in zooming from a wide-angle limit to a telephoto limit at the time of image taking,
• ωW is a half view angle (°) at a wide-angle limit,
• fT is a focal length of the entire system at a telephoto limit, and
• fW is a focal length of the entire system at a wide-angle limit.

A camera for converting an optical image of an object into an electric image signal and then performing at least one of displaying and storing of the converted image signal, comprising

• an imaging device including a zoom lens system that forms the optical image of the object and an image sensor that converts the optical image formed by the zoom lens system into the electric image signal, wherein
• in the zoom lens system,
• the zoom lens system, in order from an object side to an image side, comprises a first lens unit having positive optical power, a second lens unit having negative optical power, a third lens unit having positive optical power, and a fourth lens unit having positive optical power, wherein
• the first lens unit is composed of three or fewer lens elements, wherein
• the second lens unit is composed of three lens elements, wherein
• in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit, the second lens unit, the third lens unit and the fourth lens unit are moved individually along an optical axis such that air spaces between the individual lens units should vary, so that variable magnification is achieved, and wherein
• the following conditions (7), (8), (a-2) and (b) are satisfied:
• −3.12≦TG1/fW≦−2.36 (7)
• 1.26≦TG2/fW≦1.78 (8)
• ωW≧37 (a-2)
• fT/fw≧10 (b)
• where,
• TG1 is an amount of axial movement of the first lens unit from the object side to the image side in zooming from a wide-angle limit to a telephoto limit at the time of image taking,
• TG2 is an amount of axial movement of the second lens unit from the object side to the image side in zooming from a wide-angle limit to a telephoto limit at the time of image taking,
• ωW is a half view angle (°) at a wide-angle limit,
• fT is a focal length of the entire system at a telephoto limit, and
• fW is a focal length of the entire system at a wide-angle limit.

A zoom lens system, in order from an object side to an image side, comprising a first lens unit having positive optical power, a second lens unit having negative optical power, a third lens unit having positive optical power, and a fourth lens unit having positive optical power, wherein

• the first lens unit is composed of three or fewer lens elements, wherein
• the second lens unit is composed of three lens elements, wherein
• in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit, the second lens unit, the third lens unit and the fourth lens unit are moved individually along an optical axis such that air spaces between the individual lens units should vary, so that variable magnification is achieved, and wherein
• the following conditions (9), (a-2) and (b) are satisfied:
• 0.64≦fG4/fG1≦0.82 (9)
• ωW≧37 (a-2)
• fT/fW≧10 (b)
• where,
• fG1 is a composite focal length of the first lens unit,
• fG4 is a composite focal length of the fourth lens unit,
• ωW is a half view angle (°) at a wide-angle limit,
• fT is a focal length of the entire system at a telephoto limit, and
• fW is a focal length of the entire system at a wide-angle limit.

An imaging device capable of outputting an optical image of an object as an electric image signal, comprising:

• a zoom lens system that forms the optical image of the object;
• and
• an image sensor that converts the optical image formed by the zoom lens system into the electric image signal, wherein
• in the zoom lens system,
• the zoom lens system, in order from an object side to an image side, comprises a first lens unit having positive optical power, a second lens unit having negative optical power, a third lens unit having positive optical power, and a fourth lens unit having positive optical power, wherein
• the first lens unit is composed of three or fewer lens elements, wherein
• the second lens unit is composed of three lens elements, wherein
• in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit, the second lens unit, the third lens unit and the fourth lens unit are moved individually along an optical axis such that air spaces between the individual lens units should vary, so that variable magnification is achieved, and wherein
• the following conditions (9), (a-2) and (b) are satisfied:
• 0.64≦fG4/fG1≦0.82 (9)
• ωW≧37 (a-2)
• fT/fW≧10 (b)
• where,
• fG1 is a composite focal length of the first lens unit,
• fG4 is a composite focal length of the fourth lens unit,
• ωW is a half view angle (°) at a wide-angle limit,
• fT is a focal length of the entire system at a telephoto limit, and
• fW is a focal length of the entire system at a wide-angle limit.

A camera for converting an optical image of an object into an electric image signal and then performing at least one of displaying and storing of the converted image signal, comprising

• an imaging device including a zoom lens system that forms the optical image of the object and an image sensor that converts the optical image formed by the zoom lens system into the electric image signal, wherein
• in the zoom lens system,
• the zoom lens system, in order from an object side to an image side, comprises a first lens unit having positive optical power, a second lens unit having negative optical power, a third lens unit having positive optical power, and a fourth lens unit having positive optical power, wherein
• the first lens unit is composed of three or fewer lens elements, wherein
• the second lens unit is composed of three lens elements, wherein
• in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit, the second lens unit, the third lens unit and the fourth lens unit are moved individually along an optical axis such that air spaces between the individual lens units should vary, so that variable magnification is achieved, and wherein
• the following conditions (9), (a-2) and (b) are satisfied:
• 0.64≦fG4/fG1≦0.82 (9)
• ωW≧37 (a-2)
• fT/fW≧10 (b)
• where,
• fG1 is a composite focal length of the first lens unit,
• fG4 is a composite focal length of the fourth lens unit,
• ωW is a half view angle (°) at a wide-angle limit,
• fT is a focal length of the entire system at a telephoto limit, and
• fW is a focal length of the entire system at a wide-angle limit.