# US 4,394,072 A · Zoom lens

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- Number: US 4,394,072 A
- Document ID: US4394072A
- Status: Granted
- Kind: A
- Application number: 06/213,611
- Filed: 1980-12-05
- Granted: 1983-07-19
- Earliest claimed: 1980-12-05
- Assignees: Vivitar Corporation
- Inventors: Ellis I. Betensky
- Web page: https://patentgrep.com/patent/US4394072A

## CPC

- G02B 15/22: with movable lens means specially adapted for focusing at close distances
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS

## Abstract

A new and improved zoom lens comprises four groups. The powers of the groups from the object end to the image end are positive, negative, negative, and positive, respectively. The first group is stationery for zooming but moves for close focusing. The second and third groups move in the same direction for zooming.

## Claims

### Claim 1

A zoom lens comprising from the object end a first positive group, a second negative group, a third negative group, and a fourth positive group, said second group being a singlet and the absolute value of the ratio of the power of said second group to said first group is less than 1.75, said fourth group from the object end comprising a positive doublet followed by a positive lens and a negative lens.

### Claim 2 (depends on 1)

The lens of claim 1 wherein said first group moves for focusing and comprises a positive doublet and a positive singlet.

### Claim 3 (depends on 1)

The lens of claim 1 wherein
0.6 K.sub.P /K.sub.N 1.1
where K.sub.P and K.sub.N are the powers of the positive lens and the negative lens, respectively, in the fourth group following said doublet.

### Claim 4 (depends on 1)

A lens according to claim 1 having semi-field angles of 5.8.degree. to 14.0.degree. as scaled to a 24.times.36 mm image frame defined substantially as follows:
______________________________________ Axial Distance Index of Abbe Ele- Radius of Between Surfaces Refraction No. ment Curvature (mm) (mm) N.sub.d V.sub.d ______________________________________ R1 = 81.696 L1 3.000 1.785 25.7 R2 = 56.586 L2 9.000 1.517 64.2 R3 = -645.055 .350 R4 = 177.622 L3 3.400 1.517 64.2 R5 = 478.244 34.130 R6 = -349.635 L4 2.800 1.517 64.2 R7 = 152.834 25.583 R8 = -96.724 L5 1.800 1.658 50.9 R9 = 26.756 L6 4.500 1.785 25.7 R10 = 60.178 1.500 R11 = 29.226 L7 8.500 1.569 56.0 R12 = -26.067 L8 1.500 1.785 25.7 R13 = -295.353 14.002 R14 = 276.742 L9 3.600 1.785 25.7 R15 = -36.733 6.452 R16 = -21.177 L10 1.500 1.673 32.2 R17 = -136.403 BFL = 69.10 ______________________________________
where L1-L10 are lens elements from the object end to the image end successively;
R1-R17 are the radii of the element surfaces successively from the object end to the image end;
positive radii represent surface elements convex to the object end and negative radii represent surfaces concave to the object end;
N.sub.d is the index of refraction of the elements, and V.sub.d is the dispersion of the elements as measured by the Abbe number;
BFL is the back focal length.

### Claim 5 (depends on 1)

A lens according to claim 1 having semi-field angles of 5.7.degree. to 14.0.degree. as scaled to a 24.times.36 mm image frame defined substantially as follows:
______________________________________ Axial Distance Index of Abbe Ele- Radius of Between Surfaces Refraction No. ment Curvature (mm) (mm) N.sub.d V.sub.d ______________________________________ R1 = 77.143 L1 3.500 1.785 25.7 R2 = 50.796 L2 8.000 1.517 64.2 R3 = -424.888 .350 R4 = 138.883 L3 4.000 1.517 64.2 R5 = 279.201 51.938 R6 = -240.108 L4 2.800 1.517 64.2 R7 = 93.515 8.386 R8 = -81.076 L5 1.800 1.717 48.0 R9 = 20.653 L6 4.500 1.785 25.7 R10 = 64.103 1.500 R11 = 32.581 L7 8.500 1.569 56.0 R12 = -21.688 L8 1.500 1.785 25.7 R13 = -108.157 13.343 R14 = 346.679 L9 5.446 1.785 25.7 R15 = -35.622 7.223 R16 = -22.672 L10 1.500 1.785 25.7 R17 = -68.521 BFL = 75.03 ______________________________________
where L1-L10 are lens elements from the object end to the image end successively;
R1-R17 are the radii of the element surfaces successively from the object end to the image end;
positive radii represent surface elements convex to the object end and negative radii represent surfaces concave to the object end;
N.sub.d is the index of refraction of the elements, and V.sub.d is the dispersion of the elements as measured by the Abbe number;
BFL is the back focal length.

### Claim 6 (depends on 1)

A lens according to claim 1 having semi-field angles of 5.7.degree. to 14.0.degree. as scaled to a 24.times.36 mm image frame defined substantially as follows:
______________________________________ Axial Distance Index of Abbe Ele- Radius of Between Surfaces Refraction No. ment Curvature (mm) (mm) N.sub.d V.sub.d ______________________________________ R1 = 71.898 L1 3.500 1.785 25.7 R2 = 47.938 L2 8.000 1.517 64.2 R3 = -472.407 .350 R4 = 128.700 L3 4.000 1.517 64.2 R5 = 198.079 54.432 R6 = -176.961 L4 1.500 1.517 64.2 R7 = 82.431 8.315 R8 = -91.809 L5 1.500 1.720 50.3 R9 = 22.717 L6 4.000 1.762 26.6 R10 = 83.346 1.500 R11 = 30.913 L7 8.000 1.531 62.1 R12 = -23.367 L8 1.500 1.785 25.7 R13 = -116.769 12.859 R14 = 142.709 L9 5.446 1.785 25.7 R15 = -41.534 9.466 R16 = -22.573 L10 1.500 1.785 25.7 R17 = -76.322 BFL = 73.46 ______________________________________
where L1-L10 are lens elements from the object end to the image end successively;
R1-R17 are the radii of the element surfaces successively from the object end to the image end;
positive radii represent surface elements convex to the object end and negative radii represent surfaces concave to the object end;
N.sub.d is the index of refraction of the elements, and V.sub.d is the dispersion of the elements as measured by the Abbe number;
BFL is the back focal length.

### Claim 7 (depends on 1)

A lens according to claim 1 having semi-field angles of 5.7.degree. to 14.0.degree. as scaled to a 24.times.36 mm image frame defined substantially as follows:
______________________________________ Axial Distance Index of Abbe Ele- Radius of Between Surfaces Refraction No. ment Curvature (mm) (mm) N.sub.d V.sub.d ______________________________________ R1 = 82.993 L1 3.500 1.785 25.7 R2 = 53.332 .506 R3 = 52.534 L2 8.000 1.517 64.2 R4 = -689.814 .350 R5 = 127.303 L3 4.000 1.517 64.2 R6 = 296.800 54.419 R7 = -136.062 L4 1.500 1.517 64.2 R8 = 72.268 8.315 R9 = -110.011 L5 1.500 1.720 50.3 R10 = 25.693 L6 4.000 1.762 26.6 R11 = 108.283 1.500 R12 = 32.691 L7 8.000 1.531 62.1 R13 = -24.326 L8 1.500 1.785 25.7 R14 = -116.540 13.483 R15 = 161.822 L9 5.446 1.785 25.7 R16 = -42.920 9.919 R17 = -23.606 L10 1.500 1.785 25.7 R18 = -81.128 BFL = 76.56 ______________________________________
where L1-L10 are lens elements from the object end to the image end successively;
R1-R18 are the radii of the element surfaces successively from the object end to the image end;
positive radii represent surface elements convex to the object end and negative radii represent surfaces concave to the object end;
N.sub.d is the index of refraction of the elements, and V.sub.d is the dispersion of the elements as measured by the Abbe number;
BFL is the back focal length.

### Claim 8 (depends on 1)

A lens according to claim 1 having semi-field angles of 5.7.degree. to 14.0.degree. as scaled to 24.times.36 mm image frame defined substantially as follows:
______________________________________ Axial Distance Index of Abbe Ele- Radius of Between Surfaces Refraction No. ment Curvature (mm) (mm) N.sub.d V.sub.d ______________________________________ R1 = 77.754 L1 3.500 1.785 25.7 R2 = 51.376 L2 8.000 1.517 64.2 R3 = -420.433 .350 R4 = 134.035 L3 4.000 1.517 64.2 R5 = 259.541 52.485 R6 = -177.941 L4 2.800 1.517 64.2 R7 = 77.435 7.268 R8 = -57.296 L5 4.500 1.762 26.6 R9 = -21.372 L6 1.800 1.694 53.3 R10 = 123.126 1.500 R11 = 31.323 L7 8.500 1.569 56.0 R12 = -21.549 L8 1.500 1.785 26.1 R13 = -112.601 13.013 R14 = 350.487 L9 5.446 1.785 25.7 R15 = -34.561 6.956 R16 = -21.836 L10 1.500 1.785 25.7 R17 = -74.150 BFL = 77.19 ______________________________________
where L1-L10 are lens elements from the object end to the image end successively;
R1-R17 are the radii of the element surfaces successively from the object to the image end;
positive radii represent surface elements convex to the object end and negative radii represent surfaces concave to the object end;
N.sub.d is the index of refraction of the elements, and V.sub.d is the dispersion of the elements as measured by the Abbe number;
BFL is the back focal length.

### Claim 9 (depends on 1)

A lens according to claim 1 having semi-field angles of 5.7.degree. to 14.0.degree. as scaled to 24.times.36 mm image frame defined substantially as follows:
______________________________________ Axial Distance Index of Abbe Ele- Radius of Between Surfaces Refraction No. ment Curvature (mm) (mm) N.sub.d V.sub.d ______________________________________ R1 = 65.576 L1 3.500 1.805 25.5 R2 = 44.684 1.972 R3 = 46.026 L2 8.000 1.517 64.2 R4 = -317.625 59.836 R5 = -146.243 L3 1.500 1.517 64.2 R6 = 103.458 8.112 R7 = -93.560 L4 1.500 1.620 60.3 R8 = 27.901 L5 3.000 1.785 25.7 R9 = 59.343 1.000 R10 = 147.878 L6 4.000 1.517 64.2 R11 = -128.265 .200 R12 = 45.685 L7 6.200 1.517 64.2 R13 = -35.570 L8 1.500 1.785 25.7 R14 = -137.296 20.646 R15 = -339.846 L9 6.000 1.785 25.7 R16 = -56.094 18.339 R17 = -28.316 L10 1.500 1.785 25.7 R18 = -68.920 BFL = 55.92 ______________________________________
where L1-L10 are lens elements from the object end to the image end successively;
R1-R18 are the radii of the element surfaces successively from the object end to the image end;
positive radii represent surface elements convex to the object end and negative radii represent surfaces concave to the object end;
N.sub.d is the index of refraction of the elements, and V.sub.d is the dispersion of the elements as measured by the Abbe number;
BFL is the back focal length.

### Claim 10 (depends on 1)

A lens according to claim 1 having semi-field angles of 5.7.degree. to 14.0.degree. as scaled to a 24.times.36 mm image frame defined substantially as follows:
______________________________________ Axial Distance Index of Abbe Ele- Radius of Between Surfaces Refraction No. ment Curvature (mm) (mm) N.sub.d V.sub.d ______________________________________ R1 78.528 L1 3.500 1.785 25.7 R2 = 50.985 L2 11.600 1.517 64.2 R3 = -271.843 .350 R4 = 80.093 L3 4.000 1.510 63.4 R5 = 106.058 47.814 R6 = -125.522 L4 1.500 1.517 64.2 R7 = 54.778 8.931 R8 = -84.673 L5 1.500 1.589 61.3 R9 = 30.794 L6 3.000 1.785 25.7 R10 = 72.230 1.000 R11 = 121.524 L7 4.000 1.517 64.2 R12 = -128.412 .200 R13 = 38.478 L8 6.200 1.517 64.2 R14 = -43.290 L9 1.500 1.785 25.7 R15 = -608.956 20.194 R16 = -559.111 L10 6.000 1.785 25.7 R17 = - 56.639 14.265 R18 = -26.390 L11 1.500 1.785 25.7 R19 - -50.872 BFL = 65.19 ______________________________________
where L1-L11 are lens elements from the object end to the image end successively;
R1-R19 are the radii of the element surfaces successively from the object end to the image end;
positive radii represent surface elements convex to the object end and negative radii represent surfaces concave to the object end;
N.sub.d is the index of refraction of the elements, and V.sub.d is the dispersion of the elements as measured by the Abbe number;
BFL is the back focal length.