Zoom optical system, and imaging system incorporating the same

Abstract

The invention relates to a zoom optical system wherein various aberrations are corrected while the total thickness of a lens arrangement upon received at a collapsible lens mount is reduced thereby ensuring compactness, high image-formation capabilities, and high zoom ratios at the wide-angle end, and an imaging system that incorporates the same. The zoom optical system comprises a first lens group Gof negative refracting power and a second lens group Gof positive refracting power. The first lens group Gcomprises a negative single lens comprising at least one aspheric surface and a positive single lens with an air separation interposed between the negative single lens and the positive single lens. The second lens group Gcomprises a positive lens, a cemented lens consisting of a positive lens and a negative lens and a positive lens, and comprises at least one aspheric surface. Zooming is carried out by varying a spacing between the respective lens groups. The zoom optical system satisfies condition (1) that defines the proper range of the refracting power profile for the first lens group G, condition (2) that defines an angle-of-view range at the wide-angle end, and condition (3) that defines an angle-of-view range at the telephoto end.