Patent ID: 8325423

Claim:
A zoom lens system comprising in order from an object side to an image side: a first lens unit having a positive refracting power; a second lens unit having a negative refracting power; a third lens unit having a positive refracting power; and a fourth lens unit having a positive refracting power, wherein at the time of zooming from a wide angle end to a telephoto end, each of distances between the first lens unit and the second lens unit, the second lens unit and the third lens unit, the third lens unit and the fourth lens unit is changed, and the third lens unit comprises a first cemented lens component having a concave image-side surface on the image side, and a second cemented lens component having a concave object-side surface on the object side, which is disposed immediately after the image side of the first cemented lens component, and the first cemented lens component includes a positive lens, and a negative lens having a concave image-side surface which is disposed on the image side of the positive lens, and the second cemented lens component includes a negative lens having a concave object-side surface on the object side, and a positive lens which is disposed on the image side of the negative lens.