The zoom of this invention comprises a first lens group having a positive refracting power, a second lens group having an negative refracting power, a third lens group having a positive refracting power, a fourth lens group having a positive refracting power, and a fifth lens group having a negative refracting power from an object side in this order, wherein a zooming is carried out by moving the second and the fourth lens groups, wherein the first lens group comprises, a foreside lens group having an negative refracting power, an optical element for folding an optical path, and a backside lens group having a positive refracting power from the object side, and a condition of 1.0<.beta.5<1.9 is satisfied, provided that an imaging power of the fifth lens group where an object distance is at infinity is .beta.5.