Zoom lens system

A zoom lens comprising, in order from the image magnifying side to the image reducing side:

• a negative power first lens group which is moved axially for focusing a lens system of the zoom lens and fixed during zooming the lens system,
• a positive power second lens group,
• a positive power third lens group,
• a negative power fourth lens group, and
• a fifth lens group which has a positive power and remains fixed during focusing and zooming the lens system,
• wherein each of the second, third, and fourth lens groups is adapted to move axially with respect to all others of the first, second, third, and fourth lens groups, and wherein said zoom lens satisfies the following conditions:
• -2.0<F.sub.1 /F<-0.9
• 0.9<F.sub.2 /F<1.5
• 1.5<F.sub.3 /F<5.0
• 0.8<F.sub.5 /F<1.5
• where F is the overall focal length of the zoom lens at the wide angle end, and F.sub.1, F.sub.2, F.sub.3, and F.sub.5 are the focal lengths of the first, second, third and fifth lens groups, respectively.