An optical system comprises, at least, in order from an object side, a first lens group having positive refracting power, a second lens group having negative refracting power, a third lens group having positive refracting power, and a fourth lens group having positive refracting power, wherein at least, the second lens group and the fourth lens group move along an optical axis when magnification is changed from a wide angle end to a telephoto end, and the first lens group contains a light path reflecting element having refracting power.