Wide-angle lens

Claim 2

A wide-angle lens having a long back focal distance and comprising a negative front lens group and a positive rear lens group spaced therefrom; a diaphragm arranged in the rear lens group; the front lens group including a first negative meniscus and a second negative meniscus and a binconvex component lens therebetween; the rear lens group including a first positive lens sub-group and a second positive lens sub-group and a binconcave component lens therebetween; the second positive lens sub-group in the direction of light travel including a positive meniscus having a concave surface which faces the diaphragm and a biconvex component lens, wherein the improvement comprises: a. a first positive lens element in the positive rear lens group which comprises in the direction of light travel a positive meniscus and a binconvex component lens with the diaphragm being arranged therebetween and the concave surface of the positive meniscus facing the diagphragm; b. a spacing (d6) between the rear vertex of the front lens group and the front vertex of the rear lens group being smaller than 0.35 times the focal length of the whole wide-angle lens; c. a spacing (d6) between the rear vertex of the front lens group and the front vertex of the rear lens group plus a lens thickness (d7) of the positive meniscus in the first positive lens element in the rear lens group being smaller than 0.60 times the focal length of the whole wide-angle lens; d. a distance between the diaphragm and the front vertex of the front lens group being smaller than 1.30 times the focal length of the whole widE-angle lens; e. an index of refraction (ne) of the negative menisci of the front lens group which is smaller than 1.50 each and corresponding Abbe numbers ve which are higher than 65 each; and f. an Abbe number ve of the biconvex component lens in the front lens groups which is higher than 40; said lens members having substantially the following approximate specifications: back focal distance s'' 1.368 a relative opening of f : 2.8 a viewing angle of + OR - 38* a focal length of f 1.0 ri di ne ve Delta ne/ri r1 + 1.1167 di 0.0982 1.48914 70.22 +0.4380 r2 + 0.6392 d2 0.2321 -0.7652 r3 +3.0037 d3 0.1143 1.60889 43.63 +0.2027 r4 -3.8735 d4 0.0036 +0.1572 r5 +2.9281 d5 0.0657 1.48914 70.22 +0.1670 r6 +0.4488 d6 0.3289 -1.0900 r7 +0.7972 d7 0.2500 1.67133 41.64 +0.8421 r8 +1.3600 d8 0.1071 diaphragm area 0.4936 r9 +1.4836 d9 0.1232 1.69401 54.48 +0.4678 r10 1.9806 d10 0.1054 +0.3504 r11 -1.2140 d11 0.0393 1.79180 25.87 -0.6522 r12 +1.3360 d12 0.0571 -0.5927 r13 -1.4663 d13 0.0786 1.69401 54.48 -0.4733 r14 -0.7251 d14 0.0036 +0.9571 r15 +4.1484 d15 0.1071 1.69401 54.48 +0.1673 r16 1.0019 +0.6027 wherein r1, r2, ri. . . represent the radii of curvature of the respective elements in the direction of light travel; d1, d2, di. . . represent the axial thicknesses of the respective elements and the air spaces of the adjacent elements in the direction of light travel; ne . . . represent the refractive indices of the respective elements; ve . . . represent the Abbe numbers of the respective elements; and Delta ne/ri represent the surface powers of the respective elements.

Claim 3

A wide-angle lens having a long back focal distance and comprising a negative front lens group and a positive rear lens group; the front lens group including a first negative meniscus and a second negative meniscus and a binconvex component lens therebetween; the rear lens group including a first positive lens sub-group and a second positive lens sub-group and a biconcave component lens therebetween; the second positive lens sub-group in the direction of light travel including a positive meniscus having a concave surface which faces the diaphragm and a biconvex component lens, wherein the improvement comprises: a. a first positive lens element in the positive rear lens group which comprises in the direction of light travel a positive meniscus and a biconvex component lens with the diaphragm being arranged therebetween and the concave surface of the positive meniscus facing the diaphragm; b. a spacing (d6) between the rear vertex of the front lens group and the front vertex of the rear lens group being smaller than 0.35 times the focal length of the whole wide-angle lens; c. a spacing (d6) between the rear vertex of the front lens group and the front vertex of the rear lens group plus A lens thickness (d7) of the positive meniscus in the first positive lens element in the rear lens group being smaller than 0.60 times the focal length of the whole wide-angle lens; d. a distance between the diaphragm and the front vertex of the front lens group being smaller than 1.30 times the focal length of the whole wide-angle lens; e. an index of refraction (ne) of the negative menisci of the front lens group which is smaller than 1.50 each and corresponding Abbe numbers ve which are higher than 65 each; and f. an Abbe number ve of the binconvex component lens in the front lens group which is higher than 40; said lens members having substantially the following approximate specifications: a back focal distance s'' 1.368 a relative opening of f : 2.8 a viewing angle of + or - 38* a focal length of f 1.0 ri di ne ve Delta ne/ri r1 +1.2176 d1 0.0982 1.48914 70.22 +0.4017 r2 +0.6248 d2 0.2321 -0.7829 r3 +2.0990 d3 0.1143 1.69232 49.18 +0.3298 r4 -3.7819 d4 0.0036 +0.1831 r5 +10.6548 d5 0.0657 1.48914 70.22 +0.0459 r6 +0.4473 d6 0.3289 -1.0936 r7 +0.8361 d7 0.2500 1.67341 46.83 +0.8055 r8 +1.5835 d8 0.1071 diaphragm area -0.4253 r9 +1.4698 d9 0.1232 1.69401 54.58 +0.4722 r10 -2.2895 d10 0.1054 +0.3031 r11 -2.0951 d11 0.0393 1.79180 25.87 -0.3779 r12 +1.1189 d12 0.0571 -0.7077 r13 -1.3097 d13 0.0786 1.64304 59.85 -0.4910 r14 -0.7182 d14 0.0036 +0.8954 r15 +2.8537 d15 0.1071 1.64304 59.85 +0.2253 r16 -1.0710 +0.6004 wherein r1, r2, ri . . . represent the radii of curvature of the respective elements in the direction of light travel; d1, d2, di . . . represent the axial thicknesses of the respective elements and the air spaces of the adjacent elements in the direction of light travel; ne . . . represent the refractive indices of the respective elements; ve . . . represent the Abbe numbers of the respective elements; and Delta ne/ri . . . represent the surface powers of the respective elements.

Claim 4

A wide-angle lens having a long back focal distance and comprising a negative front lens group and a positive rear lens group; the front lens group including a first negative meniscus and a second negative meniscus and a binconvex component lens therebetween; the rear lens group including a first positive lens sub-group and a second positive lens sub-group and a biconcave component lens therebetween; the second positive lens sub-group in the direction of light travel including a positive meniscus having a concave surface which faces the diaphragm and a biconvex component lens, wherein the improvement comprises: a. a first positive lens element in the positive rear lens group which comprises in the direction of light travel a positive meniscus and a biconvex component lens with the diaphragm being arranged therebetween and the concave surface of the positive meniscus facing the diaphragm; b. a spacing (d6) between the rear vertex of the front lens group and the front vertex of the rear lens group being smaller than 0.35 times the focal length of the whole wide-angle lens; c. a spacing (d6) between the rear vertex of the front lens group and the front vertex of the rear lens group plus A lens thickness (d7) of the positive meniscus in the first positive lens element in the rear lens group being smaller than 0.60 times the focal length of the whole wide-angle lens; d. a distance between the diaphragm and the front vertex of the front lens group being smaller than 1.30 times the focal length of the whole wide-angle lens; e. an index of refraction (ne) of the negative menisci of the front lens group which is smaller than 1.50 each and corresponding Abbe numbers ve which are higher than 65 each; and f. an Abbe number ve of the binconvex component lens in the front lens group which is higher than 40; said lens members having substantially the following approximate specifications: a back focal distance s'' 1.368 a relative opening of f : 2.8 a viewing angle of + or - 38* a focal length of f 1.0 ri di ne ve Delta ne/ri r1 +1.2176 d1 0.0982 1.48914 70.22 +0.4017 r2 +0.6248 d2 0.2321 -0.7829 r3 +2.0990 d3 0.1143 1.69232 49.18 +0.3298 r4 -3.7819 d4 0.0036 +0.1831 r5 +10.6548 d5 0.0657 1.48914 70.22 +0.0459 r6 +0.4473 d6 0.3289 -1.0936 r7 +0.8361 d7 0.2500 1.67341 46.83 +0.8055 r8 +1.5835 d8 0.1071 diaphragm area -0.4253 r9 +1.4698 d9 0.1232 1.69401 54.58 +0.4722 r10 -2.2895 d10 0.1054 +0.3031 r11 -2.0951 d11 0.0393 1.79180 25.87 -0.3779 r12 +1.1189 d12 0.0571 -0.7077 r13 -1.3097 d13 0.0786 1.64304 59.85 -0.4910 r14 -0.7182 d14 0.0036 +0.8954 r15 +2.8537 d15 0.1071 1.64304 59.85 +0.2253 r16 -1.0710 +0.6004 wherein r1, r2, ri . . . represent the radii of curvature of the respective elements in the direction of light travel; d1, d2, di . . . represent the axial thicknesses of the respective elements and the air spaces of the adjacent elements in the direction of light travel; ne . . . represent the refractive indices of the respective elements; ve . . . represent the Abbe numbers of the respective elements; and Delta ne/ri . . . represent the surface powers of the respective elements.

Claim 5

A wide-angle lens having a long back focal distance and comprising a negative front lens group and a positive rear lens group spaced therefrom; a diaphragm arranged in the rear lens group; the front lens group including a first negative meniscus and a second negative meniscus and a biconvex component lens therebetween; the rear lens group including a first positive lens sub-group and a second positive lens sub-group and a biconcave component lens therebetween; the second positive lens sub-group in the direction of light travel including a positive meniscus having a concave surface which faces the diaphragm and a biconvex component lens, wherein the improvement comprises: a. a first positive lens element in the positive rear lens group which comprises in the direction of light travel a positive meniscus and a biconvex component lens with the diaphragm being arranged therebetween and the concave surface of the positIve meniscus facing the diaphragm; b. a spacing (d6) between the rear vertex of the front lens group and the front vertex of the rear lens group being smaller than 0.35 times the focal length of the whole wide-angle lens; c. a spacing (d6) between the rear vertex of the front lens group and the front vertex of the rear lens group plus a lens thickness (d7) of the positive meniscus in the first positive lens element in the rear group being smaller than 0.60 times the focal length of the whole wide-angle lens; d. a distance between the diaphragm and the front vertex of the front lens group being smaller than 1.30 times the focal length of the whole wide-angle lens; e. an index of refraction (ne) of the negative menisci of the front lens group which is smaller than 1.50 each and corresponding Abbe numbers ve which are higher than 65 each; and f. an Abbe number ve of the biconvex component lens in the front lens group which is higher than 40; said lens members having substantially the following approximate specifications : a back focal distance s'' 1.373 a relative opening of f : 2.8 a viewing angle of + or - 38* a focal length of f 1.0 r i di ne ve Delta ne/ri r 1 +1.1168 d1 0.0938 1.48914 70.22 +0.4380 r2 +0.6502 d2 0.2320 -0.7523 r3 +2.5134 d3 0.1063 1.67133 41.64 +0.2671 r4 -5.1781 d4 0.0036 +0.1296 r5 -2.6916 d5 0.0659 1.48914 70.22 +0.1817 r6 +0.4386 d6 0.3330 -1.1151 r7 +0.8065 d7 0.2499 1.67341 46.82 +0.8349 r8 +1.3128 d8 0.1074 diaphragm area -0.5130 r9 +2.1461 d9 0.1343 1.69401 54.48 +0.3234 r10 -1.6137 d10 0.1053 +0.4301 r11 -1.1436 d11 0.0394 1.79180 25.87 -0.6924 r12 +1.6062 d12 0.0573 -0.4930 r13 -1.4697 d13 0.0788 1.69401 54.48 -0.4722 r14 -0.7285 d14 0.0036 +0.9527 r15 +4.1926 d15 0.1071 1.69401 54.48 30 0.1655 r16 -0.9818 +0.7069 wherein r1, r2, ri . . . represent the radii of curvature of the respective elements in the direction of light travel; d1, d2, di . . . represent the axial thicknesses of the respective elements and the air spaces of the adjacent elements in the direction of light travel; ne . . . represent the refractive indices of the respective elements; ve . . . represent the Abbe numbers of the respective elements; and Delta ne/ri . . . represent the surface powers of the respective elements.

Claim 6

A wide-angle lens having a long back focal distance and comprising a negative front lens group and a positive rear lens group spaced therefrom; a diaphragm arranged in the rear lens group; the front lens group including a first negative meniscus and a second negative meniscus and a biconvex component lens therebetween; the rear lens group including a first positive lens sub-group and a second positive lens sub-group and a biconcave component lens therebetween; the second positive lens sub-group in the direction of light travel including a positive meniscus having a concave surface which faces the diaphragm and a biconvex component lens, wherein the improvement comprises: a. a first positive lens element in the positive rear lens group which comprises in the direction of light travel a positive meniscus and a biconvex component lens with the diaphragm being arranged therebetween and the concave surface of the positIve meniscus facing the diaphragm; b. a spacing (d6) between the rear vertex of the front lens group and the front vertex of the rear lens group being smaller than 0.35 times the focal length of the whole wide-angle lens; c. a spacing (d6) between the rear vertex of the front lens group and the front vertex of the rear lens group plus a lens thickness (d7) of the positive meniscus in the first positive lens element in the rear group being smaller than 0.60 times the focal length of the whole wide-angle lens; d. a distance between the diaphragm and the front vertex of the front lens group being smaller than 1.30 times the focal length of the whole wide-angle lens; e. an index of refraction (ne) of the negative menisci of the front lens group which is smaller than 1.50 each and corresponding Abbe numbers ve which are higher than 65 each; and f. an Abbe number ve of the biconvex component lens in the front lens group which is higher than 40; said lens members having substantially the following approximate specifications : a back focal distance s'' 1.373 a relative opening of f : 2.8 a viewing angle of + or - 38* a focal length of f 1.0 r i di ne ve Delta ne/ri r 1 +1.1168 d1 0.0938 1.48914 70.22 +0.4380 r2 +0.6502 d2 0.2320 -0.7523 r3 +2.5134 d3 0.1063 1.67133 41.64 +0.2671 r4 -5.1781 d4 0.0036 +0.1296 r5 -2.6916 d5 0.0659 1.48914 70.22 +0.1817 r6 +0.4386 d6 0.3330 -1.1151 r7 +0.8065 d7 0.2499 1.67341 46.82 +0.8349 r8 +1.3128 d8 0.1074 diaphragm area -0.5130 r9 +2.1461 d9 0.1343 1.69401 54.48 +0.3234 r10 -1.6137 d10 0.1053 +0.4301 r11 -1.1436 d11 0.0394 1.79180 25.87 -0.6924 r12 +1.6062 d12 0.0573 -0.4930 r13 -1.4697 d13 0.0788 1.69401 54.48 -0.4722 r14 -0.7285 d14 0.0036 +0.9527 r15 +4.1926 d15 0.1071 1.69401 54.48 30 0.1655 r16 -0.9818 +0.7069 wherein r1, r2, ri . . . represent the radii of curvature of the respective elements in the direction of light travel; d1, d2, di . . . represent the axial thicknesses of the respective elements and the air spaces of the adjacent elements in the direction of light travel; ne . . . represent the refractive indices of the respective elements; ve . . . represent the Abbe numbers of the respective elements; and Delta ne/ri . . . represent the surface powers of the respective elements.