PURPOSE: To obtain a large aperture diameter ratio wide angle lens which is small in size and has high performance by forming this lens of specific six elements in six groups.

CONSTITUTION: This large aperture diameter ratio wide angle lens is composed of the six elements in six groups consisting of lenses L1, L2 of negative meniscus, biconvex lenses L3, L5, L6 and biconcave lens L4. The lens described above is so constituted as to satisfy the following conditions when the radius of curvature of the i-th surface is defined as Ri, the spacing between the i-th surface and the (i+1)th surface as Di, the refractive index of (d) rays of the i-th surface as Ni and the Abbe number as 1:R1 is specified to 12.292, D1 to 1.30, N1 to 1.48749, 1 to 70.4, R2 to 4.729, D2 to 1.29, R3 to 34.800, D3 to 0.80, N3 to 1.51680, 3 to 64.2, R4 to 5.282, D4 to 2.96, R5 to 12.040, D5 to 2.19, N5 to 1.83400, 5 to 37.3, R6 to -17.998, D6 to 4.10, R7 to -17.299, D7 to 0.70, N7 to 1.84666, 7 to 23.8, R8 to 10.400, D8 to 0.23, R9 to 27.660, D9 to 1.94, N9 to 1.62041, 9 to 60.3, R10 to -6.861, D10 to 0.10, R11 to 9.130, D11 to 2.30, N11 to 1.58913, 11 to 61.3, R12 to -16.022.