A zoom lens system having an image shake correcting capability has, from
the object side to the image side: a first lens group having a positive
optical power, a second lens group having a negative optical power, a
third lens group having a positive optical power, a fourth lens group
having a negative optical power, and a fifth lens group having a positive
optical power. The third lens group includes a positive lens component
and a cemented lens element having a positive optical power. The cemented
lens element is moved in a direction perpendicular to the optical axis to
correct image shake, and the conditional formula 1.7