Zoom lens system

A zoom lens system comprising a positive first lens group, a negative second lens group, a positive third lens group, and a negative fourth lens group, in this order from an object,

• wherein zooming is performed by moving each of said positive first through said negative fourth lens groups along the optical axis;
• wherein said zoom lens system satisfies the following conditions:
• 0.5<(D12T−D12W)/fW<1.0 1.0<ΔX1G/ΔX4G<1.5
• wherein
• D12T designates the axial distance between said positive first lens group and said negative second lens group at the long focal length extremity;
• D12W designates the axial distance between said positive first lens group and said negative second lens group at the short focal length extremity;
• fW designates the focal length of the entire the zoom lens system at the short focal length extremity;
• ΔX1G designates the traveling distance of said positive first lens group from the short focal length extremity to the long focal length extremity;
• and
• ΔX4G designates the traveling distance of said negative fourth lens group from the short focal length extremity to the long focal length extremity