Patent ID: 8320054

Claim:
A zoom projection lens system, in order from an magnified end to an minified end thereof, comprising: a first lens group with negative refraction power, wherein the first lens group comprising a first lens with negative refraction power; and a second lens group with positive refraction power, wherein the second lens group, in order from an magnified end to an minified end of the zoom projection lens system, comprises a second lens with positive refraction power, a third lens with positive refraction power, a fourth lens with negative refraction power, and a fifth lens with positive refraction power; wherein the zoom projection lens system satisfies the following formulas: 1.9 <|F 1 /Fw|< 2.1, (1) 0.5 <|f 4 /Fw|< 0.8, (2) 0.95 <|f 5 /Fw| 1<1.2, (3) where “F 1 ”, “f 4 ” and “f 5 ” are respectively the effective focal lengths of the first lens group, the fourth lens and the fifth lens, “Fw” is the effective focal lengths of the zoom projection lens system in the wide angle state.