Zoom lens system, interchangeable lens apparatus and camera system

A zoom lens system having a plurality of lens units, each lens unit being composed of at least one lens element, the zoom lens system, in order from an object side to an image side, comprising:

• a first lens unit having positive optical power;
• a second lens unit having positive optical power;
• and
• at least two subsequent lens units, wherein
• the first lens unit moves along an optical axis at the time of zooming from a wide-angle limit to a telephoto limit,
• an interval between the second lens unit and a lens unit which is one of the at least two subsequent lens units varies at the time of zooming or at the time of focusing from an infinity in-focus condition to a close-object in-focus condition,
• the first lens unit is composed of at least three lens elements,
• each of the first lens unit and the second lens unit includes at least one lens element having negative optical power, and
• the following conditions (1) and (2) are satisfied:
• 0.008<(1/vdMIN)−(1/vdMAX)<0.028 (1)
• 0.1<|m|/(fT−fW)<0.4 (2)
• where
• vdMIN is the minimum value among Abbe numbers to the d-line of each lens element constituting the first lens unit,
• vdMAX is the maximum value among Abbe numbers to the d-line of each lens element constituting the first lens unit,
• m is the maximum value among the amounts of movement of each subsequent lens unit at the time of zooming from a wide-angle limit to a telephoto limit,
• fT is a focal length of the entire system at a telephoto limit, and
• fW is a focal length of the entire system at a wide-angle limit.