Zoom lens system, imaging device and camera

An imaging device capable of outputting an optical image of an object as an electric image signal, comprising:

• a zoom lens system that forms the optical image of the object;
• and
• an image sensor that converts the optical image formed by the zoom lens system into the electric image signal, wherein
• the zoom lens system has a plurality of lens units each composed of at least one lens element and,
• in order from an object side to an image side, comprises:
• a first lens unit having negative optical power and composed of two lens elements;
• a second lens unit having positive optical power;
• and
• a third lens unit having positive optical power, wherein
• in zooming from a wide-angle limit to a telephoto limit during image taking, the individual lens units are moved along an optical axis such that an interval between the first lens unit and the second lens unit should decrease and that an interval between the second lens unit and the third lens unit should increase, so that magnification change is achieved, and wherein
• the following condition is satisfied:
• 4.0<(DG2+(DG2A))/(DG2A)<20.0 (22)
• where,
• DG2 is an axial interval from the most object side to the most image side of the second lens unit, and
• DG2A is an axial interval from the most image side of the second lens unit to the aperture diaphragm.

A camera for converting an optical image of an object into an electric image signal and then performing at least one of displaying and storing of the converted image signal, comprising

• an imaging device including a zoom lens system that forms the optical image of the object and an image sensor that converts the optical image formed by the zoom lens system into the electric image signal, wherein
• the zoom lens system has a plurality of lens units each composed of at least one lens element and,
• in order from an object side to an image side, comprises:
• a first lens unit having negative optical power and composed of two lens elements;
• a second lens unit having positive optical power;
• and
• a third lens unit having positive optical power, wherein
• in zooming from a wide-angle limit to a telephoto limit during image taking, the individual lens units are moved along an optical axis such that an interval between the first lens unit and the second lens unit should decrease and that an interval between the second lens unit and the third lens unit should increase, so that magnification change is achieved, and wherein
• the following condition is satisfied:
• 4.0<(DG2+(DG2A))/(DG2A)<20.0 (22)
• where,
• DG2 is an axial interval from the most object side to the most image side of the second lens unit, and
• DG2A is an axial interval from the most image side of the second lens unit to the aperture diaphragm.