Zoom lens and imaging apparatus

A zoom lens of an inner focus type including a first lens group having positive refractive power, a second lens group having negative refractive power, which is movable in an optical axis direction mainly for zooming (varying power), a third lens group having positive refractive power, a fourth lens group having negative refractive power, which is movable in the optical axis direction for correcting fluctuations in focal position during zooming and for focusing, and a fifth lens group having positive refractive power, which lens groups are arrayed in order from an object side, characterized in that:

• said first lens group comprises a concave lens, a convex lens, and a triple-cemented lens in which a lens made of special low-dispersion glass is sandwiched in the middle, which lenses are arrayed in order from the object side.

An imaging apparatus having a zoom lens, imaging means for transforming an image taken in by said zoom lens to an electrical image signal, and image control means, characterized in that:

• said image control means, referring to a transformation coordinate coefficient provided in advance according to a variable power rate by said zoom lens, moves points on the image which are defined by the image signal formed by said imaging means to form a new image signal subjected to coordinate transformation and to output said new image signal,
• said zoom lens of an inner focus type having four or five lens groups, comprises at least a first lens group having positive refractive power, a second lens group having negative refractive power, which is movable in an optical axis direction mainly for zooming (varying power), a third lens group having positive refractive power, and a fourth lens group having positive or negative refractive power, which is movable in the optical axis direction for correcting fluctuations in focal position during zooming and for focusing, which lens groups are arrayed in order from an object side, and
• said first lens group comprises at least a concave lens, a convex lens, and a triple-cemented lens in which a lens made of special low-dispersion glass is sandwiched in the middle, which lenses are arrayed in order from the object.