Wide angle photographing lens

Claim 1

A wide angle photographing lens system having a large relative aperture, consisting of a first negative meniscus lens convex to the object side of the system, a second positive lens, a third negative meniscus lens convex to the object side, a fourth positive lens, a fifth negative lens cemented to said fourth positive lens, a sixth biconvex lens, a seventh biconcave lens, an eighth positive meniscus lens concave to the object side, and a ninth positive lens, said lenses being sequentially arranged in the named order in the direction away from the object, said first to fifth lenses together constituting a forward lens group and said sixth to ninth lenses together constituting a rearward lens group, said system satisfying the following conditions: fc > 3f 1/5f > (n5 - n4/r8) > 1/10f n4 n5 > 0.1 r10 > -r11 0.55f < -r12 < 0.73f 0.25f < d12 + d13 + d14 < 0.45f where r subscripts represent the radii of curvature of the successive lens surfaces; d subscripts the lens thicknesses or spacings between lenses, n subscripts the refractive indices of the lens glasses, fc the focal length of said forward lens group, and f the focal length of the entire system, the spacing d9 between said forward and rearward lens groups being variable.