Zoom lens and camera device

Abstract

The present invention provides a zoom lens which has high zoom ratio and small size and a camera device, wherein the zoom lens is provided with the following components from the object side: a first lens group which is fixed in zooming and focusing and has positive refractive power; a second lens group which moves in zooming and has negative refractive power; a third lens group which is fixed in zooming and focusing and has positive refractive power; a fourth lens group which moves in zooming and has positive refractive power; and a fifth lens group which moves in zooming and has positive refractive power. When the zoom lens zooms from a wide-angle end to the telescope end, the fifth lens firstly moves to the object side and reverses to the image side in the middle way for moving with a mode of drawing-out a moving track with a convex arc shape which projects into the object side. Furthermore the following conditional expression is satisfied, wherein deltaTM is the movement amount of the fifth lens group when zooming from a lens position of (fw*ft)<1 / 2> to a lens position of the telescope end, fw is the focal distance of the whole system of the wide angle end, and ft is the focal distance of the whole system of the telescope end. 1.4< deltaTM / fw< 3.0...(1).

Description

technical field [0001] The present invention relates to a zoom lens and an imaging device suitable for a video camera, a digital still camera, and a portable information terminal (PDA: Personal Digital Assistance). Background technique [0002] In recent years, in imaging devices such as digital still cameras, miniaturization of the entire device has been demanded as the miniaturization of imaging elements such as CCD (Charge Coupled Device) and CMOS (Complementary Metal Oxide Semiconductor) progresses. Therefore, recently, an imaging device has been developed that uses a so-called curved optical system in which an optical path of a lens system is bent halfway, thereby achieving a reduction in thickness in the depth direction when incorporated into the imaging device. [0003] In Patent Documents 1 to 3, it is disclosed that five lens groups whose refractive power is positive, negative, positive, positive, and positive are sequentially arranged from the object side. When cha...

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Problems solved by technology

[0014] Furthermore, the zoom lens described in Patent Document 3 is characterized in that the fifth lens group moves when focusing and the fifth lens has at least one positive lens and at least one negative lens in order from the object side, and the relevant lens materials satisfy prescribed conditions. Especially at the telephoto end, field curvature and chromatic aberration of magnification fluctuate greatly during focusing, so performance fluctuations during focusing are large

Furthermore, since the position of the fifth lens group is further away from the image plane at the telephoto end than at the wide-angle end, miniaturization and aberration correction throughout the zoom range become difficult

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