US 4,359,270 AGranted

Zoom lens

AssigneeAsahi Kogaku Kogyo Kabushiki Kaisha

InventorSadao Okudaira

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Abstract

A high performance zoom lens including, in order from the object side, a convergent first lens group including a cemented lens composed of a negative meniscus lens having a surface of greater curvature on the image side and a first positive meniscus lens having a surface of greater curvature on the object side and a second positive meniscus lens having a surface of greater curvature on the object side, a divergent second lens group including a negative meniscus lens having a surface of greater curvature on the image side, a biconcave lens and a positive meniscus lens having a surface of greater curvature on the object side, a convergent third lens group including a biconvex lens and a convergent fourth lens group including a cemented lens composed of a biconvex lens and a biconcave lens, a cemented lens composed of a negative meniscus lens having a surface of greater curvature on the image side and a biconvex lens, and a negative meniscus lens having a surface of greater curvature on the object side. Each of the lens groups is independently mechanically mounted so as to be movable for zooming.

Claims2

Dependent claims

A high performance zoom lens comprising, in order from the object side, a convergent first lens group including a cemented lens comprising a negative meniscus lens having a surface of greater curvature on the image side and a first positive meniscus lens having a surface of greater curvature on the object side and a second positive meniscus lens having a surface of greater curvature on the object side, a divergent second lens group including a negative meniscus lens having a surface of greater curvature on the image side, a biconcave lens and a positive meniscus lens having a surface of greater curvature on the object side, a convergent third lens group including a biconvex lens and a convergent fourth lens group including a cemented lens comprising a biconvex lens and biconcave lens, a cemented lens comprising a negative meniscus lens having a surface of greater curvature on the image side and a biconvex lens, and a negative meniscus lens having a surface of greater curvature on the object side, wherein each of said lens groups is independently mechanically movable for zooming, said zoom lens satisfying the following conditions:

______________________________________ f = 35.97 .about. 132 F No. 1:
4.1 r.sub.i d.sub.i N.sub.i .nu..sub.i ______________________________________ 1 115.000 1.80 1.84666 23.9 2 67.312 8.20 1.61800 63.4 3 388.000 0.10 4 75.596 6.22 1.67000 57.3 5 325.500 l.sub.1 6 1370.000 1.11 1.74100 52.7 7 20.382 6.16 8 -108.316 1.00 1.64328 47.9 9 49.832 2.39 10 35.571 3.28 1.84666 23.9 11 126.000 l.sub.2 12 104.599 2.31 1.77250 49.6 13 -225.000 l.sub.3 14 20.500 8.07 1.54072 47.2 15 -45.300 1.21 1.80518 25.4 16 60.078 11.01 17 56.850 2.10 1.84666 23.9 18 25.920 5.63 1.66446 35.8 19 -28.750 3.37 20 -16.827 1.20 1.88300 40.8 21 -39.006 ______________________________________ overall focal length 35.97 50.00 80.00 100.00 132.00 l.sub.1 1.47 14.79 28.04 33.34 45.64 l.sub.2 34.35 26.72 15.52 10.41 4.34 l.sub.3 5.80 3.35 1.08 0.39 1.59 ______________________________________ l.sub.3S = 5.80 = 5.37l.sub.3M f.sub.1 = 109.39 = 3.04f.sub.s .vertline.f.sub.2 .vertline. = 27.98 = 0.78f.sub.s f.sub.3 = 92.72 = 2.58f.sub.s f.sub.4 = 68.38 = 1.90f.sub.s
where r.sub.i is the radius of curvature of the i-th lens surface, d.sub.i is the lens thickness or distance between adjacent lenses, N.sub.i is the refractive index of the i-th lens, .nu..sub.i is the Abbe number of the i-th lens, f.sub.s is the overall focal length of said zoom lens at a wide angle position thereof, l.sub.3s is the distance between said third and fourth lens groups at f.sub.s, and l.sub.3M is the distance between said third and fourth lens groups at 2.22f.sub.s.

______________________________________ f = 36.00 .about. 132 F No. 1:4.1 r.sub.i d.sub.i N.sub.i .nu..sub.i ______________________________________ 1 117.780 1.80 1.84666 23.9 2 68.597 8.24 1.61800 63.4 3 435.054 0.10 4 77.697 6.13 1.67000 57.3 5 344.587 l.sub.1 6 850.409 1.11 1.74100 52.7 7 20.382 6.23 8 -106.775 1.00 1.64328 47.9 9 49.710 2.13 10 35.200 3.31 1.84666 23.9 11 127.275 l.sub.2 12 98.500 2.15 1.77250 49.6 13 -208.360 l.sub.3 14 20.253 6.60 1.54072 47.2 15 -46.218 1.21 1.80518 25.4 16 61.360 12.69 17 55.409 2.10 1.84666 23.9 18 25.647 5.55 1.66446 35.8 19 -28.799 3.39 20 -16.827 1.20 1.88300 40.8 21 -43.089 ______________________________________ overall focal length 36.00 50.00 80.00 100.00 132.00 ______________________________________ l.sub.1 1.38 13.43 26.99 35.77 47.01 l.sub.2 34.36 26.13 15.14 10.77 4.29 l.sub.3 5.97 2.89 0.53 0.46 1.19 ______________________________________ l.sub.3S = 5.97 = 11.26l.sub. 3M f.sub.1 = 110.227 = 3.06f.sub.s .vertline.f.sub.2 .vertline. = 28.26 = 0.79f.sub.s f.sub.3 = 86.84 = 2.41f.sub.s f.sub.4 = 71.73 = 1.99f.sub.s ______________________________________
where r.sub.i is the radius of curvature of the i-th lens surface, d.sub.i is the lens thickness or distance between adjacent lenses, N.sub.i is the refractive index of the i-th lens, i is the Abbe number of the i-th lens, f.sub.s is the overall focal length of said zoom lens at a wide angle position thereof, l.sub.3S is the distance between said third and fourth lens groups at f.sub.s, and l.sub.3M is the distance between said third and fourth lens groups at 2.22f.sub.s.

Dependencies are inferred from the claim text.