Zoom lens

Claim 2

A zoom lens comprising from the object side a first positive grouping movable axially for focusing, a second negative grouping, and a third positive grouping, said second and third groupings being movable simultaneously axially of said lens but in the opposite direction for varying the equivalent focal length of said lens, said third grouping comprising a front and rear sub-groupings of positive optical power, said rear sub-grouping comprises three groups which from the object end are of positive, positive and negative optical powers, successively.

Claim 3

The lens of claim 1 where said sub-groupings move at different rates as the equivalent focal length of said lens is varied.

Claim 4

The lens of claim 1 where 0.75 <TR<1.4 where TR is the telephoto ratio of the rear sub-grouping.

Claim 5

The lens of claim 1 where the optical power of said first group of said sub-grouping has an absolute ratio to the optical power of said third group of said sub-grouping of 0.5 or greater.

Claim 6

The lens of claim 4 where said ratio has an upper limit of 1.45.

Claim 7

The lens of claim 4 where the object side surface of said third group is concave.

Claim 8

The lens of claim 1 where said third grouping has a first sub-grouping on the object side with equivalent focal length f IIIa and ##EQU6## where f I is the equivalent focal length of the first grouping.

Claim 9

The lens of claim 6 where ##EQU7##

Claim 10

The lens of claim 1 where 3.2 f.sub.IIIb >f.sub.IIIa ≧f.sub.IIIb where f IIIa is the equivalent focal length of the first sub-grouping and f IIIb is the equivalent focal length of the second sub-grouping.

Claim 11

The lens of claim 7 where said first grouping comprises an object side doublet which is a negative meniscus and a bi-convex element, followed by a positive meniscus.

Claim 12

The lens of claim 7 where the front grouping is a doublet comprising a bi-concave element and a bi-convex element, followed by a bi-convex element.

Claim 13

The lens of claim 11 where the doublet is of negative optical power.

Claim 14

The lens of claim 1 where said third grouping has a first object side sub-grouping of positive power and said sub-grouping comprises from the object side a positive element and a doublet comprising a bi-concave element and a bi-convex element.

Claim 15

The lens of claim 1 where the second grouping has a first object side group comprising a negative element, and a doublet concave to the object side and convex to the image side.

Claim 16

The lens of claim 1 where the second grouping is, from the object side, a doublet comprising a bi-convex element and a bi-concave element followed by a negative element having a concave object side surface.

Claim 17

The lens of claim 1 wherein the second grouping comprises from the object side a negative optical power element, a positive meniscus element concave to the object side, and a doublet concave to the object side and convex to the image side.

Claim 18

The lens of claim 1 wherein said first sub-grouping comprises a doublet having a bi-convex element and a negative element.

Claim 19

The lens of claim 1 wherein said first sub-grouping is a doublet in the form of a negative meniscus and a bi-convex element, from the object side.

Claim 20

The lens of claim 1 wherein said first sub-grouping comprises a positive single element and a weak optical power doublet which includes a bi-convex element.

Claim 21

A zoom lens comprising from the object side a first positive grouping movable axially for focusing, a second negative grouping, a third positive grouping, said second and third groupings being movable axially simultaneously but in the opposite direction for varying the equivalent focal length of said lens, said third grouping comprising front and rear sub-groupings of positive optical power, said rear sub-grouping having a telephoto ratio of 0.75 to 1.4 and the ratio of the equivalent focal length of the first sub-grouping to that of the second sub-grouping of from 1.0 to 3.2.

Claim 22

A zoom lens comprising from the object side a first positive grouping movable axially for focusing, a second negative grouping, a third positive grouping, said second and third groupings being movable axially simultaneously but in the opposite direction for varying the equivalent focal length of said lens, said third grouping comprising front and rear sub-groupings of positive optical power, said rear sub-grouping having a telephoto ratio of 0.75 to 1.4 and the ratio of the equivalent focal length of the first sub-grouping to that of the second sub-grouping of from 1.0 to 3.2.

Claim 23

The lens of claim 20 where said sub-groupings move at different rates as the equivalent focal length of the lens is changed.

Claim 24

A zoom lens comprising from the object side a first positive grouping movable axially for focusing, a second negative group, and a third positive grouping, said second and third groupings being movable simultaneously axially of said lens, but in opposite directions for varying the equivalent focal length of said lens, said third grouping comprising front and rear sub-groupings of positive optical power, said rear sub-grouping comprising from the object end a first positive group, a second positive group, and a third negative group, the absolute value of the ratio of the optical power of the first positive group to the third negative group being 0.5 or greater, said third negative group having a concave object side surface.

Claim 25

A zoom lens comprising from the object side a first positive grouping movable axially for focusing, a second negative group, and a third positive grouping, said second and third groupings being movable simultaneously axially of said lens, but in opposite directions for varying the equivalent focal length of said lens, said third grouping comprising front and rear sub-groupings of positive optical power, said rear sub-grouping comprising from the object end a first positive group, a second positive group, and a third negative group, the absolute value of the ratio of the optical power of the first positive group to the third negative group being 0.5 or greater, said third negative group having a concave object side surface.

Claim 26

A lens according to claim 1 having semi-field angles of 22.8° to 6.3° as scaled to a 24×36 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 = -331.909 L1 2.000 1.847 23.8 R2 = 77.893 L2 8.325 1.531 50.9 R3 = -105.577 0.200 R4 = 75.550 L3 5.264 1.741 35.1 R5 = -738.126 1.000 R6 = -273.757 L4 4.990 1.847 23.8 R7 = -39.174 L5 2.000 1.697 55.5 R8 = 74.538 4.086 R9 = -53.121 L6 1.500 1.697 55.5 R10 = 148.879 49.510 R11 = 46.961 L7 4.902 1.608 40.0 R12 = -929.669 0.200 R13 = 726.860 L8 6.485 1.587 51.7 R14 = -31.445 L9 1.500 1.847 23.8 R15 = -260.591 10.825 R16 = 23.960 L10 8.148 1.517 69.7 R17 = 249.885 11.397 R18 = 64.858 L11 1.500 1.804 46.5 R19 = 16.770 0.467 R20 = 18.004 L12 6.440 1.648 33.8 R21 = -46.653 2.692 R22 = -18.862 L13 1.500 1.834 37.3 R23 = -106.740 ______________________________________ Where L1-L13 are lens elements from the object end to the image end successively. R1-R23 are the radii of the element surfaces successively from the object to image 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 th Abbe number.

Claim 27

A lens according to claim 1 having semi-field angles of 22.8° to 6.3° as scaled to a 24×36 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 = 91.606 L1 6.157 1.517 69.7 R2 = -204.977 0.200 R3 = 99.209 L2 6.256 1.487 70.4 R4 = -121.897 L3 2.000 1.847 23.8 R5 = -1311.231 1.000 R6 = -207.668 L4 1.500 1.713 53.9 R7 = 39.369 4.571 R8 = -48.686 L5 2.000 1.697 55.5 R9 = 39.043 L6 4.988 1.847 23.8 R10 = -564.889 46.831 R11 = 54.481 L7 5.338 1.607 56.7 R12 = -374.746 0.200 R13 = 77.405 L8 7.895 1.581 40.9 R14 = -36.501 L9 1.500 1.847 23.8 R15 = 194.707 9.109 R16 = 26.911 L10 8.076 1.525 60.0 R17 = -1041.865 9.346 R18 = 52.178 L11 1.838 1.559 64.4 R19 = 21.897 3.425 R20 = 28.087 L12 5.298 1.627 34.6 R21 = -62.138 2.562 R22 = -23.600 L13 1.500 1.834 37.3 R23 = 28.021 0.445 R24 = 28.914 L14 4.385 1.619 35.4 R25 = -118.264 ______________________________________ Where L1-L14 are lens elements from the object end to the image end successively. R1-R25 are the radii of the element surfaces successively from the object to image 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 th Abbe number.

Claim 28

A lens according to claim 1 having semi-field angles of 22.8° to 6.3° as scaled to a 24×36 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 = 311.481 L1 2.000 1.847 23.8 R2 = 68.476 L2 9.718 1.589 62.6 R3 = -108.672 0.200 R4 = 50.060 L3 4.222 1.690 31.0 R5 = 84.784 2.822 R6 = 508.164 L4 5.563 1.847 23.8 R7 = -47.257 L5 2.000 1.696 55.1 R8 = 41.931 5.239 R9 = -38.143 L6 1.500 1.711 53.9 R10 = Infinity 47.717 R11 = 59.518 L7 7.648 1.571 51.1 R12 = -30.945 L8 1.500 1.831 24.2 R13 = -106.827 4.906 R14 = 22.295 L9 7.351 1.487 70.4 R15 = 85.618 18.021 R16 = 54.725 L10 5.731 1.631 34.2 R17 = - 16.627 L11 1.500 1.806 40.7 R18 = -68.855 2.363 R19 = -19.620 L12 1.500 1.806 40.7 R20 = -53.856 ______________________________________ Where L1-L12 are lens elements from the object end to the image end successively. R1-R20 are the radii of the element surfaces successively from the object to image 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 th Abbe number.

Claim 29

A lens according to claim 1 having semi-field angles of 27.8° to 6.3° as scaled to a 24×36 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 = 87.088 L1 6.073 1.487 70.4 R2 = -357.220 0.200 R3 = 81.894 L2 6.904 1.517 69.7 R4 = -113.558 L3 2.000 1.805 25.5 R5 = -741.212 1.000 R6 = -145.203 L4 2.000 1.850 32.2 R7 = 29.227 5.027 R8 = -40.720 L5 3.218 1.617 36.6 R9 = -28.743 0.329 R10 = -34.696 L6 2.000 1.620 60.3 R11 = 30.644 L7 4.602 1.847 23.8 R12 = -836.811 47.970 R13 = 244.236 L8 3.347 1.847 23.8 R14 = -159.720 0.200 R15 = 37.449 L9 7.464 1.487 70.4 R16 = -59.792 1.500 1.847 23.8 L10 R17 = 128.574 14.245 R18 = 34.377 L11 7.312 1.694 53.3 R19 = 125.375 12.722 R20 = 40.777 L12 1.500 1.834 37.3 R21 = 17.194 L13 8.377 1.529 51.6 R22 = -45.367 4.500 R23 = -23.943 L14 1.500 1.850 32.2 R24 = 50.260 0.724 R25 = 56.060 L15 3.971 1.847 23.8 R26 = -75.126 ______________________________________ Where L1-L15 are lens elements from the object end to the image end successively. R1-R26 are the radii of the element surfaces successively from the object to image 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 th Abbe number.

Claim 30

A lens according to claim 1 having semi-field angles of 22.8° to 6.3° as scaled to a 24×36 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 = 51.685 L1 2.000 1.728 28.7 R2 = 35.419 L2 11.322 1.487 70.4 R3 = -300.792 0.200 R4 = 70.392 L3 4.236 1.487 70.4 R5 = 260.451 2.174 R6 = -218.893 L4 1.500 1.773 49.6 R7 = 33.369 5.032 R8 = -50.332 L5 1.500 1.697 55.5 R9 = 29.315 L6 5.544 1.847 23.8 R10 = 372.944 39.191 R11 = 278.949 L7 3.349 1.785 25.7 R12 = -112.134 0.200 R13 = 37.648 L8 8.126 1.487 70.4 R14 = -46.741 L9 1.500 1.728 28.7 R15 = 130.107 12.937 R16 = 30.554 L10 5.344 1.589 61.3 R17 = 161.993 9.765 R18 = 53.104 L11 1.500 1.805 25.5 R19 = 26.732 0.998 R20 = 35.956 L12 4.621 1.603 60.7 R21 = -86.528 10.000 R22 = -20.688 L13 1.200 1.773 49.6 R23 = 36.746 L14 6.262 1.673 32.2 R24 = -36.746 ______________________________________ Where L1-L14 are lens elements from the object end to the image end successively. R1-R24 are the radii of the element surfaces successively from the object to image 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 th Abbe number.

Claim 31

A lens according to claim 1 having semi-field angles of 22.8° to 6.3° as scaled to a 24×36 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 = 101.687 L1 7.471 1.487 70.4 R2 = -198.419 0.200 R3 = 95.447 L2 7.353 1.487 70.4 R4 = -139.520 L3 2.000 1.805 25.5 R5 = -5325.160 2.883 R6 = -190.880 L4 1.500 1.773 49.7 R7 = 48.001 5.742 R8 = -58.215 L5 2.000 1.697 55.5 R9 = 42.255 L6 4.992 1.847 23.8 R10 = 2180.742 50.035 R11 = 154.385 L7 3.104 1.847 23.8 R12 = -536.964 0.200 R13 = 34.221 L8 8.851 1.487 70.4 R14 = -42.312 L9 1.500 1.805 25.5 R15 = 124.660 5.006 R16 = 27.114 L10 5.691 1.581 40.9 R17 = 167.817 6.077 R18 = 35.204 L11 1.500 1.847 23.8 R19 = 22.920 1.620 R20 = 36.325 L12 6.578 1.541 47.2 R21 = -83.500 8.928 R22 = -18.143 L13 1.500 1.834 37.3 R23 = 114.343 0.617 R24 = 278.786 L14 3.152 1.847 23.8 R25 = -35.211 ______________________________________ Where L1-L14 are lens elements from the object end to the image end successively. R1-R25 are the radii of the element surfaces successively from the object to image 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 th Abbe number.

Claim 32

A lens according to claim 1 having semi-field angles of 22.8° to 6.3° as scaled to a 24×36 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 = 100.000 L1 2.000 1.847 23.8 R2 = 61.777 L2 8.540 1.487 70.4 R3 = -139.015 0.200 R4 = 57.007 L3 4.333 1.487 70.4 R5 = 141.831 1.774 R6 = -219.606 L4 1.500 1.773 49.7 R7 = 42.712 4.608 R8 = -50.056 L5 2.000 1.697 55.5 R9 = 39.784 L6 4.992 1.847 23.8 R10 = -1453.300 47.246 R11 = 93.289 L7 3.836 1.805 25.5 R12 = -218.835 0.200 R13 = 37.170 L8 7.645 1.487 70.4 R15 = -60.263 L9 1.500 1.847 23.8 R15 = 74.160 8.989 R16 = 28.233 L10 5.691 1.583 45.7 R17 = 161.805 8.196 R18 = 41.946 L11 1.500 1.847 23.8 R19 = 23.983 1.133 R20 = 33.166 L12 4.571 1.532 48.8 R21 = -115.744 11.000 R22 = -18.977 L13 1.500 1.834 37.3 R23 = 73.633 0.505 R24 = 94.636 L14 5.041 1.785 25.7 R25 = -31.880 ______________________________________ Where L1-L14 are lens elements from the object end to the image end successively. R1-R25 are the radii of the element surfaces successively from the object to image 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 th Abbe number.

Claim 33

A lens according to claim 1 having semi-field angles of 22.8° to 6.3° as scaled to a 24×36 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 = 94.324 L1 6.157 1.517 69.7 R2 = -225.278 0.200 R3 = 107.461 L2 6.256 1.487 70.4 R5 = -125.129 L3 2.000 1.847 23.8 R5 = -998.950 1.000 R6 = -175.603 L4 1.500 1.713 53.9 R7 = 42.006 4.571 R8 = -55.596 L5 2.000 1.697 55.5 R9 = 38.480 L6 4.988 1.847 23.8 R10 = -2603.400 46.933 R11 = 57.230 L7 5.338 1.607 56.7 R12 = -355.668 0.200 R13 = 97.881 L8 7.895 1.581 40.9 R15 = -38.031 L9 1.500 1.847 23.8 R15 = 383.703 10.275 R16 = 26.072 L10 8.076 1.517 69.7 R17 = 264.855 11.774 R18 = 57.188 L11 2.581 1.487 70.4 R19 = 157.667 0.588 R20 = 132.141 L12 1.500 1.786 43.9 R21 = 17.553 0.559 R22 = 18.852 L13 6.418 1.648 33.8 R23 = -54.308 2.694 R24 = -20.096 L14 1.500 1.800 42.3 R25 = -96.886 ______________________________________ Where L1-L14 are lens elements from the object end to the image end successively. R1-R25 are the radii of the element surfaces successively from the object to image 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 th Abbe number.

Claim 34

A lens according to claim 1 having semi-field angles of 22.8° to 8.2° as scaled to a 24×36 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 = 43.818 L1 2.00 1.805 25.5 R2 = 30.325 L2 9.03 1.487 70.4 R3 = 660.800 0.20 R4 = 57.757 L3 4.58 1.487 70.4 R5 = -2198.63 2.00 R6 = -172.476 L4 1.50 1.786 43.9 R7 = 23.666 4.44 R8 = -37.599 L5 1.50 1.487 70.4 R9 = 27.572 L6 4.19 1.847 23.8 R10 = 215.640 .88 R11 = 58.063 L7 2.76 1.785 25.7 R12 = 451.184 .20 R13 = 40.879 L8 6.43 1.487 70.4 R14 = -30.890 L9 1.50 1.805 25.3 R15 = 179.032 4.64 R16 = 26.196 L10 5.72 1.487 70.4 R17 = - 122.438 11.13 R18 = 54.654 L11 1.50 1.834 37.3 R19 = 17.104 0.37 R20 = 17.908 L12 5.14 1.626 35.5 R21 = -77.945 5.29 R22 = -17.046 L13 1.50 1.743 49.2 R23 = 40.228 ______________________________________ Where L1-L13 are lens elements from the object end to the image end successively. R1-R23 are the radii of the element surfaces successively from the object to image 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 th Abbe number.

Claim 35

A lens according to claim 1 having semi-field angles of 29.6° to 8.4° as scaled to a 24×36 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 = 84.075 L1 2.000 1.824 32.4 R2 = 35.070 L2 10.644 1.487 70.4 R3 = Infinity 0.200 R4 = 42.216 L3 7.293 1.640 60.2 R5 = -551.202 1.417 R6 = 3577.318 L4 1.500 1.773 49.6 R7 = 22.455 4.403 R8 = -36.651 L5 1.500 1.697 55.5 R9 = 23.130 L6 4.494 1.847 23.8 R10 = 305.162 27.789 R11 = 182.035 L7 3.349 1.805 25.5 R12 = -83.526 .200 R13 = 31.013 L8 6.560 1.487 70.4 R14 = -39.407 L9 1.500 1.789 27.5 R15 = 83.438 19.239 R16 = 24.898 L10 5.344 1.592 60.5 R17 = 131.219 4.888 R18 = 51.764 L11 1.500 1.805 25.5 R19 = 22.511 1.477 R20 = 32.129 L12 6.196 1.599 62.1 R21 = -44.403 6.00 R22 = -18.935 L13 1.200 1.764 47.9 R23 = 31.004 L14 7.807 1.692 36.9 R24 = -31.715 ______________________________________ Where L1-L14 are lens elements from the object end to the image end successively. R1-R24 are the radii of the element surfaces successively from the object to image 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 th Abbe number.

Claim 36

A lens according to claim 1 having semi-field angles of 22.8° to 8.5° as scaled to a 24×36 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 = 154.274 L1 2.000 1.805 25.5 R2 = 60.625 L2 7.482 1.603 60.7 R3 = -166.752 0.200 R4 = 49.425 L3 4.711 1.487 70.4 R5 = 976.009 2.000 R6 = -111.965 L4 1.500 1.834 37.3 R7 = 29.937 4.683 R8 = -40.282 L5 1.500 1.487 70.4 R9 = 34.267 L6 4.190 1.847 23.8 R10 = -661.409 37.179 R11 = 58.780 L7 3.370 1.785 25.7 R12 = 588.325 0.200 R13 = 40.593 L8 6.062 1.518 59.0 R14 = -38.790 L9 1.500 1.805 25.5 R15 = 60.207 0.200 R16 = 29.884 L10 4.661 1.603 60.7 R17 = Infinity 15.024 R18 = 47.488 L11 1.500 1.834 37.3 R19 = 17.934 0.309 R20 = 18.509 L12 5.462 1.632 34.8 R21 = -62.404 6.267 R22 = -19.946 L13 1.500 1.834 37.3 R23 = -58.480 ______________________________________ Where L1-L13 are lens elements from the object end to the image end successively. R1-R23 are the radii of the element surfaces successively from the object to image 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 th Abbe number.

Claim 37

A lens according to claim 1 having semi-field angles of 22.7° to 6.4° as scaled to a 24×36 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 = 61.614 L1 3.000 1.805 25.5 R2 = 43.179 L2 11.800 1.487 70.4 R3 = -262.146 0.200 R4 = 57.758 L3 3.500 1.487 70.4 R5 = 84.442 32.117 R6 = -1317.271 L4 1.500 1.804 46.5 R7 = 36.278 5.516 R8 = -44.483 L5 1.500 1.773 49.6 R9 = 34.734 L6 5.000 1.847 23.8 R10 = -219.127 3.250 R11 = 234.035 L7 3.350 1.699 30.1 R12 = -89.453 0.200 R13 = 43.887 L8 6.600 1.487 70.4 R14 = -58.165 L9 1.500 1.785 26.1 R15 = 117.280 1.000 R16 = 43.796 L10 4.200 1.487 70.4 R17 = 1423.188 0.200 R18 = 25.838 L11 5.600 1.487 70.4 R19 = 64.901 4.495 R20 = 27.729 L12 2.000 1.805 25.5 R21 = 18.696 8.570 R22 = 72.878 L13 4.900 1.487 70.4 R23 = -31.396 2.125 R24 = -23.175 L14 1.200 1.804 46.5 R25 = 43.273 0.571 R26 = 46.400 L15 3.900 1.805 25.5 R27 = -124.368 ______________________________________ Where L1-L15 are lens elements from the object end to the image end successively. R1-R27 are the radii of the element surfaces successively from the object to image 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 th Abbe number.

Claim 38

A lens according to claim 1 having semi-field angles of 22.8° to 6.4° as scaled to a 24×36 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 = 76.881 L1 3.000 1.805 25.5 R2 = 48.966 L2 12.250 1.487 70.4 R3 = -164.561 0.210 R4 = 45.744 L3 3.500 1.517 64.2 R5 = 64.414 30.449 R6 = 230.226 L4 1.500 1.713 53.9 R7 = 32.025 5.200 R8 = -39.590 L5 1.500 1.773 49.6 R9 = 36.704 L6 5.000 1.847 23.8 R10 = -235.177 3.750 R11 = -166.537 L7 2.800 1.785 26.1 R12 = -72.127 0.200 R13 = 46.928 L8 7.300 1.487 70.4 R14 = -50.494 L9 1.500 1.785 26.1 R15 = 526.365 1.010 R16 = 64.334 L10 4.200 1.487 70.4 R17 = -211.416 0.200 R18 = 29.665 L11 5.450 1.487 70.4 R19 = 76.428 9.370 R20 = 26.516 L12 2.000 1.847 23.8 R21 = 19.733 6.680 R22 = 64.036 L13 5.200 1.487 70.4 R23 = -30.409 1.280 R24 = -25.289 L14 1.200 1.804 46.5 R25 = 52.130 3.230 R26 = 62.262 L15 4.280 1.805 25.5 R27 = -189.602 ______________________________________ Where L1-L15 are lens elements from the object end to the image end successively. R1-R27 are the radii of the element surfaces successively from the object to image 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 th Abbe number.

Claim 39

The lens of claim 1 wherein: 0.3≦fI/FVD≦0.6 0.10≦|fII/FVD|≦0.25 0.3≦fIIIa/FVD≦1.2 0.3≦fIIIb/FVD≦0.6 Where fI is the effective focal length of said first grouping, fII is the equivalent focal length of said second grouping, fIIIa is the equivalent focal length of said front sub-grouping, fIIIb is the equivalent focal length of said rear sub-grouping, and FVD is the front vertex distance of the lens.

Claim 40

The lens of claim 1 wherein the telephoto ratio of said rear sub-grouping is less than 1.