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.