Magnification change optical system and image pickup device

摘要

In magnification change optical system, although being small-sized, it possesses large aperture ratio and high magnification change ratio, it actualizes high optical efficiency closely from visible spectrum extending through the infrared limits. Magnification change optical system, from object side has negative 1st lens group (G1) and the correct 2nd lens group (G2) for order, interval of these optical axis directions changes at the time of the magnification change. The 1st, 2nd lens respectively, is the negative single lens and the correct single lens which direct the concave surface to object side from image side of the 1st lens group (G1). The 2nd lens group (G2), from object side most includes the 2nd connecting lens which consists of the 1st connecting lens, the negative lens and the correct lens which consist of the correct lens, the negative lens and the correct lens which at least possess the aspheric surface of 1 where it is arranged on object side aspects in order. The negative lens which forms the 1st connecting lens, the negative lens which forms the 2nd connecting lens together the surface of image side is the concave surface. In addition, the conditional expression regarding the surface form of the correct lens which forms the 1st connecting lens is satisfied.