Wide angle photographic lens

Claim 2

A wide angle photographic lens system comprising in the order from the object side, a first lens component which is a positive lens having its more convex surface facing the object side, a second lens component which is a negative meniscus lens having its convex surface facing the object side, a third lens component which is a biconvex lens having its more convex surface facing the object side, a diaphragm, a fourth lens component which is a biconcave lens, a fifth lens component which is a positive meniscus lens having its convex surface facing the image side, and a sixth lens component which is a biconvex lens, said lens system satisfying the following conditions: 1.5f < |f.sub.12 | < 1.75f (1) 5.0 <f.sub.1 /|f.sub.2 | < 8.0 (2) 0.1 <d.sub.1 + d.sub.2 + d.sub.3 /d.sub.4 < 0.35 (3) 0.5f < r.sub.4 < 0.6f (4) where f is the total focal length of the lens system, f 1 and f 2 are the focal lengths of the first and the second lens components, respectively, f 12 is the combined focal length of the first and second lens components, r 4 is the curvature radius of the surface of the second lens component which faces the image side, d 1 and d 3 are the center thicknesses of the first and the second lens components, respectively, and d 2 and d 4 are the air spaces between the first and second lens components and between the second and third lens components, respectively.

Claim 3

A lens system according to claim 1, wherein the numerical data are as shown in the following table: ______________________________________ Thicknesses and Refractive Abbe Radii air spaces indexes numbers ______________________________________ r.sub.1 = 386.719 d.sub.1 = 9.199 nd.sub.1 = 1.62374 γd.sub.1 = 47.0 r.sub.2 = 1871.551 d.sub.2 = 0.343 r.sub.3 = 167.545 d.sub.3 = 4.909 nd.sub.2 = 1.62041 γd.sub.2 = 60.3 r.sub.4 = 55.370 d.sub.4 = 93.708 r.sub.5 = 85.216 d.sub.5 = 9.611 nd.sub.3 = 1.70154 γd.sub.3 = 41.1 r.sub.6 = -197.175 d.sub.6 = 19.222 r.sub.7 = -77.840 d.sub.7 = 15.446 nd.sub.4 = 1.7552 γd.sub.4 = 27.5 r.sub.8 = 120.630 d.sub.8 = 3.776 r.sub.9 = -265.822 d.sub.9 = 9.268 nd.sub.5 = 1.62041 γd.sub.5 = 60.3 r.sub. 10 = -64.116 d.sub.10 = 0.343 r.sub.11 = 285.350 d.sub.11 = 8.581 nd.sub.6 = 1.58913 γd.sub.6 = 61.2 r.sub.12 = -150.156 ______________________________________

Claim 4

A lens system according to claim 1, wherein the numerical data are as shown in the following table: ______________________________________ Thicknesses and Refractive Abbe Radii air spaces indexes Numbers ______________________________________ r.sub.1 = 897.870 d.sub.1 = 8.026 nd.sub.1 = 1.62374 γd.sub.1 = 47.0 r.sub.2 = -3310.382 d.sub.2 = 0.343 r.sub.3 = 136.893 d.sub.3 = 4.253 nd.sub.2 = 1.62041 γd.sub.2 = 60.3 r.sub.4 = 53.140 d.sub.4 = 93.631 r.sub.5 = 84.333 d.sub.5 = 9.603 nd.sub.3 = 1.70154 γd.sub.3 = 41.1 r.sub.6 = -174.397 d.sub.6 = 19.206 r.sub.7 = -76.308 d.sub.7 = 15.434 nd.sub.4 = 1.7552 γd.sub.4 = 27.5 r.sub.8 = 115.280 d.sub.8 = 3.773 r.sub.9 = -306.739 d.sub.9 = 9.260 nd.sub.5 = 1.62041 γd.sub.5 = 60.3 r.sub.10 = -64.352 d.sub.10 = 0.343 r.sub.11 = 287.241 d.sub.11 = 8.574 nd.sub.6 = 1.58913 γd.sub.6 = 61.2 r.sub.12 = -166.025 ______________________________________

Claim 5

A lens system according to claim 1, wherein the numerical data are as shown in the following table: ______________________________________ Thicknesses and Refractive Abbe Radii air spaces indexes numbers ______________________________________ r.sub.1 = 367.133 d.sub.1 = 12.226 nd.sub.1 = 1.60323 γd.sub.1 = 42.5 r.sub.2 = 3881.119 d.sub.2 = 2.448 r.sub.3 = 180.070 d.sub.3 = 5.594 nd.sub.2 = 1.58913 γd.sub.2 = 61.2 r.sub.4 = 51.923 d.sub.4 = 80.420 r.sub.5 = 90.210 d.sub.5 = 16.434 nd.sub.3 = 1.72342 γd.sub.3 = 38.0 r.sub.6 = -202.098 d.sub.6 = 18.531 r.sub.7 = -81.119 d.sub.7 = 12.238 nd.sub.4 = 1.80518 γd.sub.4 = 25.5 r.sub.8 = 128.671 d.sub.8 = 6.643 r.sub.9 = -699.301 d.sub.9 = 12.937 nd.sub.5 = 1.713 γd.sub.5 = 53.9 r.sub.10 = -70.175 d.sub.10 = 1.049 r.sub.11 = 262.238 d.sub.11 = 9.091 nd.sub.6 = 1.5168 γd.sub.6 = 64.2 r.sub.12 = 174.275 ______________________________________

Claim 6

A lens system according to claim 1, wherein the numerical data are as shown in the following table: ______________________________________ Thicknesses and Refractive Abbe Radii air spaces indexes numbers ______________________________________ r.sub.1 = 349.650 d.sub.1 = 13.986 nd.sub.1 = 1.60323 γd.sub.1 = 42.5 r.sub.2 = 3461.538 d.sub.2 = 2.448 r.sub.3 = 171.329 d.sub.3 = 5.594 nd.sub.2 = 1.62041 γd.sub.1 = 60.3 r.sub.4 = 52.448 d.sub.4 = 80.420 r.sub.5 = 87.413 d.sub.5 = 11.189 nd.sub.3 = 1.72342 γd.sub.3 = 38.0 r.sub.6 = -228.479 d.sub.6 = 18.182 r.sub.7 = -85.564 d.sub.7 = 13.986 nd.sub.4 = 1.78470 γd.sub.4 = 26.1 r.sub.8 = 117.626 d.sub.8 = 6.643 r.sub.9 = -699.301 d.sub.9 = 11.888 nd.sub.5 = 1.69680 γd.sub.5 = 55.6 r.sub.10 = -68.706 d.sub.10 = 1.049 r.sub.11 = 227.273 d.sub.11 = 9.091 nd.sub.6 = 1.48749 γd.sub.6 = 70.0 r.sub.12 = -182,003 ______________________________________

Claim 7

A lens system according to claim 1, wherein the numerical data are as shown in the following table: ______________________________________ Thicknesses and Refractive Abbe Radii air spaces indexes numbers ______________________________________ r.sub.1 = 356.822 d.sub.1 = 10.490 nd.sub.1 = 1.62374 γd.sub.1 = 47.0 r.sub.2 = 2169.231 d.sub.2 = 0.350 r.sub.3 = 199.301 d.sub.3 = 5.594 nd.sub.2 = 1.62041 γd.sub.2 = 60.3 r.sub.4 = 55.245 d.sub.4 = 95.455 r.sub.5 = 84.965 d.sub.5 = 9.790 nd.sub.3 =1.70154 γd.sub.3 = 41.1 r.sub.6 = -187.203 d.sub.6 = 19.580 r.sub.7 = -75.150 d.sub.7 = 15.734 nd.sub.4 = 1.7552 γd.sub.4 = 27.5 r.sub.8 = 122.028 d.sub.8 = 3.846 r.sub.9 = -314.685 d.sub.9 = 9.441 nd.sub.5 = 1.62041 γd.sub.5 = 60.3 r.sub.10 = -63.217 d.sub.10 = 0.350 r.sub.11 = 286.713 d.sub.11 = 8.741 nd.sub.6 = 1.58913 γd.sub.6 = 61.2 r.sub.12 = -174.126 ______________________________________