Wideangle four group zoom lens

Abstract

A wideangle zoom lens has four lens groups including a first lens group having a negative refractive power, a second group having a positive refractive power, a third lens group having a negative refractive power and a fourth lens group having a positive refractive power. The first to fourth lens groups being arranged object side in that order. The zooming operation from a wideangle end to a telephoto end is performed by increasing the distance between the second and third lens groups while reducing the distance betwen the third and fourth lens groups. Zooming is performed by non-linearly moving the first lens group. The first to fourth lens groups are arranged to meet the following conditions: 3.0<F2/FW<4.4 2.3<F4/FW<3.5 3.1<.vertline..beta.3W.vertline.<3.95 wherein Fi indicates the focal distance of the i-th lens group, FW indicates the focal distance of the whole lens system at the wideangle end and .beta.3W indicates the imaging lateral magnification of the third lens group at the wideangle end.

Dependencies are inferred from the claim text.