Patent ID: 8154648

Claim:
A zoom lens system comprising, in order from an object side: a first lens unit having a negative refracting power; a second lens unit having a positive refracting power; a third lens unit having a positive refracting power; and a fourth lens unit having a negative refracting power, wherein at the time of zooming from a wide angle end to a telephoto end, the second lens unit moves such that a distance between the first lens unit and the second lens unit decreases, and distances between the other lens units change, and the first lens unit comprises in order from the object side, one negative lens component having an aspheric surface at least on one surface, and one positive lens component, and the total number of lens components in the first lens unit is two, and the fourth lens unit comprises one negative lens component having a surface on the object side as a concave surface, and the total number of lens components in the fourth lens unit is one, and the zoom lens system satisfies the following conditional expression (1A) −4<( R 4a +R 4b )/( R 4a −R 4b )<−0.5 (1A) where, R 4a denotes a paraxial radius of curvature of a surface on the object side, of the negative lens component in the fourth lens unit, and R 4b denotes a paraxial radius of curvature of a surface on an image side, of the negative lens component in the fourth lens unit.