Zoom lens system, imaging device and camera

A 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 negative optical power;
• a third lens unit having positive optical power;
• and
• one or more subsequent lens units, wherein
• in zooming from a wide-angle limit to a telephoto limit at the time of image taking, the first lens unit, the second lens unit, and the third lens unit are moved along an optical axis to perform magnification change,
• a lens unit α which is one of the subsequent lens units does not move along the optical axis at the time of the zooming, but moves along the optical axis at the time of transition from an imaging state to an accommodated state, and
• the following conditions (1), (2-1) and (a) are satisfied:
• 0.8<LT/fT<1.2 (1)
• 0.12<Dα/fGα<0.30 (2-1)
• fT/fW>9.0 (a)
• where,
• LT is an overall length of lens system (a distance from a most object side surface of the first lens unit to an image surface) at a telephoto limit,
• Dα is an axial air-equivalent length between a most image side surface of the lens unit α and the image surface,
• fGα is a composite focal length of the lens unit α,
• fW is a focal length of the entire system at a wide-angle limit, and
• fT is a focal length of the entire system at a telephoto limit.