Variable magnification optical system, optical equipment, imaging equipment and method for manufacturing variable magnification optical system

Abstract

A variable magnification optical system comprises, in order from an object side, a first lens group Ghaving positive refractive power, a second lens group Ghaving negative refractive power, a third lens group Ghaving positive refractive power and a fourth lens group Ghaving negative refractive power; upon varying a magnification, a distance between the first lens group Gand the second lens group Gbeing varied, a distance between the second lens group Gand the third lens group Gbeing varied, and a distance between the third lens group Gand the fourth lens group Gbeing varied; upon focusing, the fourth lens group Gbeing moved; and a predetermined conditional expression being satisfied. With such a configuration, there is provided a variable magnification optical system whose focusing lens group is compact in size and reduced in weight, so high speed and quiet focusing can be effected without lens barrel being made large in size, and further by which variations in aberrations upon varying magnification from the wide angle end state to the telephoto end state as well as variations in aberrations upon focusing from the infinite distance object to the close distance object can be superbly suppressed.