PURPOSE: To hold various aberrations in excellent states by allowing a lens system which consists of the 1st convergent group and divergent group and the 2nd convergent group to meet specific requirements.

CONSTITUTION: This lens system consists of the 1st convergent group of four lenses, i.e. the 1st positive lens, the 2nd positive lens and negative lens, and the 3rd positive lens, the divergent group of two negative lens elements which are combined lenses, and the 2nd divergent group of three lenses which are all single positive, positive, and positive lenses or combined partially. Then, inequalities I , II, and III (or III') hold. In the inequalities , ν1, ν2, ν3 and ν4 are Abbe numbers of the 1st positive, the 2nd positive and negative and the 3rd positive lenses in the 1st convergent group, and θ1, θ2, θ3 and θ4 are partial dispersion ratios of the 1st positive, the 2nd positive and negative, and the 3rd positive lenses in the 1st convergent group.