Zoom lens system and camera including the same

A zoom lens system, comprising, in order from an object side to an image side:

• a first lens unit that does not move for zooming and has a positive optical power;
• a second lens unit that moves during the zooming and has a negative optical power;
• a third lens unit that moves during the zooming and has a negative optical power;
• and
• a fourth lens unit that does not move for the zooming and has a positive optical power,
• wherein the first lens unit comprises a variable apex angle prism disposed on the image side of at least one lens element;
• and
• wherein the following conditions are satisfied:
• 4.3<f1/fw<10;
• −0.8<βvw<−0.2;
• and
• −1.9<βr<−1.4,
• where fw denotes a focal length of an entire system at a wide angle end, f1 denotes a focal length of the first lens unit, βvw denotes an imaging magnification of the second lens unit at the wide angle end, and βr denotes an imaging magnification of the fourth lens unit.