A lens of variable equivalent focal length where two lens groups located on either side of an aperture defining means move relative to the aperture defining means, and a lens group of positive power is positioned close to the aperture defining means. The aperture defining means and the associated positive power group may either be stationary or move with change in equivalent focal length.
|
1. A lens of variable equivalent focal length extending from a dimension below the diagonal of the image frame of the lens to a dimension substantially above comprising from the object end a first positive group, a second negative group, an aperture defining means, a third positive group closely spaced in fixed relation to the aperture defining means, and a fourth positive group, said second first and fourth groups being movable in the same direction to vary the equivalent focal length of the lens, while said second group moves in the opposite direction, said third group and said aperture defining means remaining stationary during change in equivalent focal length, said second group being of strong negative optical power, and
5. 0>|K2 /KG |>2.0 where K2 is the optical power of said second group and KG is the geometric mean of the powers of said lens at the extremes of its equivalent focal lengths. 2. The lens of
lens. 3. The lens of claim 2 1 wherein said first and fourth groups move in fixed relation. 4. The lens of claim 1 where all of said groups move in fixed relation to focus said lens. 5. The lens of claim 1 wherein said third group comprises a single element and ##EQU2## where the image side surface of said element is defined on a radius RI and the object side surface of said element is defined on a radius Ro. 6. The lens of claim 1 wherein said third group comprises two elements. 7. The lens of claim 6 wherein said third group comprises a negative meniscus and a biconvex element. 8. The lens of claim 1 wherein: 0.3>K3 /KG ZR >0.15 where K3 is the power of the third group KG is the geometric mean of the powers of the lens at the extremes of its focal length range, and ZR is the zoom ratio of the lens. 9. The lens of claim 1 wherein: 1.3>K3 /KG >0.4 where K3 is the power of the third group, and KG is the geometric mean of the powers of the lens at the extremes of its focal length range. 10. In a lens of variable focal length, of the type where a negative group on the object side of an aperture defining means and a positive group on the image side of the aperture defining means move axially with respect to the aperture defining means to vary the equivalent focal length of the lens, the improvement comprising, a positive lens component closely, positioned to said aperture defining means and in fixed relation thereto; said aperture defining means and said positive lens component remaining stationary during variation of the equivalent focal length.
11. The lens of
0.3>K3 /KG ZR >0.15 where K3 is the power of said positive lens component KG is the geometric means of the powers of the lens at the extremes of its focal length range, and ZR is the zoom ratio of the lens. 12. The lens of
1.3>K3 /KG >0.4. 13. The lens of claim 1 where the power of said positive group in fixed relation to the aperture defining means is substantially equal to or greater than the power of said front group. 14. The lens of claim 1 where the power of said positive group in fixed relation to the aperture defining means is substantially equal to or less than the geometric mean power of said lens. 15. The lens of claim 1 where the power of said third group is substantially equal to or greater than the power of said first group and substantially equal to or less then than the geometric mean of the powers of the lens at the extremes of its equivalent focal lengths. 16. A zoom lens having a range of equivalent focal lengths from a dimension below the diagonal of the image frame of said lens to substantially above comprising means defining a variable aperture, a first positive and a second negative lens group on the object side of said aperture defining means, and a rear positive group on the image side of said aperture defining means, said first, second and rear lens groups being axially movable with respect to said aperture defining means to vary the equivalent focal length of said lens and a third positive group closely positioned to said aperture defining means and in fixed relation thereto, said third group being stationary as said other groups are moved to vary the equivalent focal length, all of said groups being movable in fixed relation to focus said lens. 17. The lens of claim 16 wherein said positive group on the object side of said negative group and said positive group on the image side of said aperture defining means move in fixed relation with variation in equivalent focal length. 18. The lens of claim 16 where the group in fixed relation to said aperture defining means has an optical power K3, the geometric mean power of said lens is KG, and lens has a zoom ratio ZR, and 0.25>K3 /KG ZR >0.15 and where K3 is the optical power of said third group, KG is the geometric mean of the optical powers of said lens at the extremes of its equivalent focal length range and ZR is the zoom ratio of said lens. 19. The lens of claim 16 where 0.006>K3 /ZR >0.003 where K3 is the optical power of said lens expressed as the reciprocal of its equivalent focal length in millimeters, and ZR is the zoom ratio of said lens. 20. The lens of claim 16 where 1.2>K3 /KG >0.4 and where K3 is the optical power of said third group, and KG is the geometric mean of the optical powers of said lens at the extremes of its equivalent focal length range. 21. A lens according to claim 1 as scaled to an equivalent focal length of 28.5 to 87.0 mm for a 24×36 mm image frame defined substantially as follows:
where L1-L13 are lens elements from the object end; S1-S15 are the lens surfaces from the object end with positive radii struck from the right and negative ratii radii struck from the left; Nd is the index of refraction of the lens element; Vd is the Abbe number of the lens elements; Z1, Z2 and Z3 are variable during change in equivalent focal length; EFL is the equivalent focal length; FVD is the front vertex distance; and BFL is the back focal length. 22. A lens according to claim 1 as scaled to an equivalent focal length of 28.5 to 87.0 mm for a 24×36 mm image frame defined substantially as follows:
where L1-L13 are lens elements from the object end; S1-S25 are the lens surfaces from the object end with positive radii struck from the right and negative radii struck from the left; Nd is the index of refraction of the lens elements; Vd is the Abbe number of the lens elements; Z1, Z2 and Z3 are variable during change in equivalent focal length; EFL is the equivalent focal length; FVD is the front vertex distance; and BFL is the back focal length. 23. A lens according to claim 1 as scaled to an equivalent focal length of 28.5 to 87.0 mm for a 24×36 mm image frame defined substantially as follows:
where L1-L13 are lens elements from the object end; S1-S25 are the lens surfaces from the object end with positive radii struck from the right and negative radii struck from the left; Nd is the index of refraction of the lens elements; Vd is the Abbe number of the lens elements; Z1, Z2, and Z3 are variable during change in equivalent focal length; EFL is the equivalent focal length; FVD is the front vertex distance; and BFL is the back focal length. 24. A lens according to claim 1 as scaled to an equivalent focal length of 25.5 to 124.0 mm for a 24×36 mm image frame defined substantially as follows:
where L1-L16 are lens elements from the object end; S1-S28 are the lens surfaces from the object end with positive radii struck from the right and negative radii struck from the left; Nd is the index of refraction of the lens elements; Vd is the Abbe number of the lens elements; Z1, Z2 and Z3 are variable during change in equivalent focal length; EFL is the equivalent focal length; FVD is the front vertex distance; and BFL is the back focal length. 25. A lens according to claim 1 as scaled to an equivalent focal length of 25.5 to 124.0 mm for a 24×36 mm image frame defined substantially as follows:
where L1-L13 are lens elements from the object end; S1-S24 are the lens surfaces from the object end with positive radii struck from the right and negative radii struck from the left; Nd is the index of refraction of the lens element; Vd is the Abbe number of the lens elements; Z1, Z2 and Z3 are variable during change in equivalent focal length; EFL is the equivalent focal length; FVD is the front vertex distance; and BFL is the back focal length. 26. A lens according to claim 1 as scaled to an equivalent focal length of 25.5 to 124.0 mm for a 24×36 mm image frame defined substantially as follows:
wherein L1-L13 are lens elements from the object end; S1-S24 are the lens surfaces from the object end with positive radii struck from the right and negative radii struck from the left; Nd is the index of refraction of the lens elements; Vd is the Abbe number of the lens elements; Z1, Z2, and Z3 are variable during change in equivalent focal length; EFL is the equivalent focal length; FVD is the front vertex distance; and BFL is the back focal length. 27. A lens according to claim 1 as scaled to an equivalent focal length of 25.5 to 124.0 mm for a 24×36 mm image frame defined substantially as follows:
where L1-L16 are lens elements from the object end; S1-S27 are the lens surfaces from the object end with positive radii struck from the right and negative radii struck from the left; Nd is the index of refraction of the lens elements; Vd is the Abbe number of the lens elements; Z1, Z2, and Z3 are variable during change in equivalent focal length; EFL is the equivalent focal length; FVD is the front vertex distance; and BFL is the back focal length. 28. A lens according to claim 1 as scaled to an equivalent focal length of 25.5 to 124.0 mm for a 24×36 mm image frame defined substantially as follows:
where L1-L16 are lens elements from the object end; S1-S27 are the lens surfaces from the object end with positive radii struck from the right and negative radii struck from the left; Nd is the index of refraction of the lens elements; Vd is the Abbe number of the lens elements; Z1, Z2 and Z3 are variable during change in equivalent focal length; EFL is the equivalent length; FVD is the front vertex distance; and BFL is the back focal length. 29. A lens of variable equivalent focal length consisting from the object end a first positive group, a second negative group, a third positive group, and a fourth positive group, an aperture defining means closely positioned to said third group and in fixed relation, said first, second and fourth groups being axially movable to vary the equivalent focal length of the lens, said third group and said aperture defining means being stationary as the equivalent focal length of the lens is varied. 30. The lens of claim 29 where 0.5<K1 /KG <1.0 2.0<|K2 /KG |<5.0 0.4<K3 /KG <1.2 0.5<K4 /KG <1.3 where K1, K2, K3 and K4 are the powers of said first, second, third and fourth groups respectively, and KG is the geometric mean of the powers of said lens at the extremes of its equivalent focal lengths. 31. A lens of variable equivalent focal length extending from a dimension below the diagonal of the image frame of the lens to a dimension substantially above for a camera having a 24×36 mm image frame comprising from the object end, a first positive group, a second negative group, a third positive group, and a fourth positive group, said first, second and fourth groups being movable simultaneously in opposite directions to vary the equivalent focal length of said lens, said first and fourth groups being movable in the same direction, said third lens group being stationary, an aperture defining means closely spaced to said third group and in fixed relation thereto, and 0.015>K1 >0.010 0.080>|K2 |>0.040 0.019>K3 >0.010 0.023>K4 >0.010 where K1, K2, K3, and K4, are the optical powers of said first, second, third, and fourth groups expressed as the reciprocal of the equivalent focal lengths in millimeters of said groups. |
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A lens embodying the invention as shown in FIGS. 1 and 1a comprises from the object end thirteen elements L1-L13 in four groups G1-G4.
Group G1 comprises a negative meniscus L1, a biconvex element L2, a positive meniscus L3, and is of overall positive power.
Group G2 comprises a negative meniscus L4, a biconcave element L5, and a relatively thick positive doublet shown as a biconvex element L6, and a negative element L7. The doublet L6, L7 is convex to the object and has a large radius image side surface which may be convex or concave to the image as shown by the prescriptions, infra.
Group G3, as shown in FIG. 1, comprises a single element L8 very closely spaced to the aperture defining means or iris I. Component L8 is convex to the object and has an image side surface defined on a very large radius RI relative to the object side radius Ro.
Group G4 comprises a biconvex element L9, a relatively thick biconcave element L10, a positive meniscus L11 convex to the image, a biconvex element L12, and a negative meniscus convex to the image.
As will hereinafter be made apparent, the third group bears a certain relationship to other parameters of the lens:
0.3<(K3 /KG ZR)<0.15
where
K3 is the optical power of the group G3
ZR is the zoom ratio of the lens, and
KG is the geometric mean power of the lens, and
KG =.sqroot.KL KS
where
KL is the power of the lens at the longest equivalent focal length, and
KS is the power of the lens at the shortest equivalent focal length.
Three examples of the lenses substantially as shown in FIGS. 1 and 1a are set forth in Tables I-III. In these examples and as shown in FIGS. 1 and 1a, groups G1 and G4 move together toward the object as the EFL increases, group G2 moves toward the image and group G3 and the aperture defining means remains stationary with respect to the focal plane FP.
In the following three examples, the prescriptions are for lenses having a 24×36 mm image frame; an equivalent focal length (EFL) range of 28.6 mm to 87.0 mm; and relative apertures which vary from f/2.9 to f/3.9 from the lower EFL to the higher EFL.
In Tables I-III, the lens elements are identified from the object to the image end by L1-L13, the lens element surfaces are S1-S25, the index of refraction is ND, and the lens element dispersion as measured by the Abbe Number is VD. The movements of the various groups are shown by the data under the heading Zoom Data for various EFL's, Z1, Z2 and Z3 are the axial spaces between groups as shown on the drawings. FVD is the front vertex distance of the lens, and BFL is the back focal length of the lens. The relative aperture at the various EFL's is given under the heading f/No.
| TABLE I |
| ______________________________________ |
| Surface Axial Distance |
| Radius Between Surfaces |
| Lens Surface (mm) (mm) Nd |
| Vd |
| ______________________________________ |
| S1 878.67 |
| L1 3.00 1.805 |
| 25.5 |
| S2 53.00 |
| 1.80 |
| S3 54.94 |
| L2 8.70 1.786 |
| 43.9 |
| S4 -295.19 |
| 0.15 |
| S5 49.87 |
| L3 4.30 1.835 |
| 43.0 |
| S6 100.18 |
| Z1 |
| S7 83.91 |
| L4 2.00 1.850 |
| 32.2 |
| S8 17.34 |
| 4.80 |
| S9 -116.10 |
| L5 2.00 1.835 |
| 43.0 |
| S10 33.18 |
| .20 |
| S11 25.25 |
| L6 11.54 1.728 |
| 28.3 |
| S12 -17.23 |
| L7 1.50 1.835 |
| 43.0 |
| S13 -826.07 |
| Z2 |
| aperture |
| 1.00 |
| S14 55.92 |
| L8 2.23 1.667 |
| 48.3 |
| S15 1165.66 |
| Z3 |
| S16 28.44 |
| L9 4.79 1.613 |
| 58.6 |
| S17 -41.59 |
| 0.79 |
| S18 -28.11 |
| L10 12.00 1.593 |
| 35.6 |
| S19 38.61 |
| 2.68 |
| S20 -145.85 |
| L11 3.00 1.835 |
| 43.0 |
| S21 -31.12 |
| 0.20 |
| S22 51.53 |
| L12 5.97 1.573 |
| 42.6 |
| S23 -23.68 |
| 0.99 |
| S24 21.43 |
| L13 1.60 1.805 |
| 25.5 |
| S25 -993.13 |
| ______________________________________ |
| ZOOM DATA |
| f/No. EFL FVD Z1 Z2 Z3 BFL |
| ______________________________________ |
| 2.9 28.6 156.4 .80 mm |
| 15.3 mm |
| 14.7 mm |
| 43.6 mm |
| mm mm |
| 3.1 40.0 161.3 10.4 10.4 10.3 48.5 |
| 3.5 55.0 165.0 18.6 6.5 6.0 53.1 |
| 3.9 87.0 171.7 29.2 1.0 0.8 58.9 |
| ______________________________________ |
| TABLE II |
| ______________________________________ |
| Surface Axial Distance |
| Radius Between Surfaces |
| Lens Surface (mm) (mm) Nd |
| Vd |
| ______________________________________ |
| S1 649.67 |
| L1 3.00 1.805 |
| 25.5 |
| S2 57.37 |
| 1.80 |
| S3 58.75 |
| L2 8.70 1.700 |
| 47.8 |
| S4 -237.36 |
| 0.15 |
| S5 52.91 |
| L3 4.30 1.834 |
| 37.3 |
| S6 120.92 |
| Z1 |
| S7 70.22 |
| L4 2.00 1.805 |
| 25.5 |
| S8 17.07 |
| 5.10 |
| S9 -64.49 |
| L5 2.00 1.589 |
| 61.3 |
| S10 25.54 |
| 0.50 |
| S11 22.97 |
| L6 7.17 1.699 |
| 30.1 |
| S12 -18.35 |
| L7 7.17 1.699 |
| 30.1 |
| S13 158.15 |
| Z2 |
| aperture |
| 1.30 |
| S14 61.35 |
| L8 2.23 1.723 |
| 38.0 |
| S15 -697.26 |
| Z3 |
| S16 31.91 |
| L9 4.79 1.658 |
| 57.3 |
| S17 -40.93 |
| 0.60 |
| S18 -28.41 |
| L10 13.30 1.593 |
| 35.5 |
| S19 40.69 |
| 2.84 |
| S10 - 65.65 |
| L11 3.00 1.583 |
| 46.5 |
| S21 -27.15 |
| 0.20 |
| S22 50.97 |
| L12 7.25 1.517 |
| 52.2 |
| S23 -23.28 |
| 1.79 |
| S24 -20.86 |
| L13 1.60 1.847 |
| 23.8 |
| S25 -56.24 |
| ______________________________________ |
| ZOOM DATA |
| f/No. EFL FVD Z1 Z2 Z3 BFL |
| ______________________________________ |
| 2.9 28.6 156.5 0.8 mm |
| 15.1 mm |
| 16.4 mm |
| 42.5 mm |
| mm mm |
| 3.2 40.0 161.8 10.6 20.4 11.3 47.8 |
| 3.5 55.0 166.7 19.0 6.7 6.6 52.8 |
| 4.0 87.0 173.3 29.8 1.8 0.8 59.3 |
| ______________________________________ |
| TABLE III |
| ______________________________________ |
| Surface Axial Distance |
| Radius Between Surfaces |
| Lens Surface (mm) (mm) Nd |
| Vd |
| ______________________________________ |
| S1 367.16 |
| L1 3.00 1.805 |
| 25.5 |
| S2 53.15 |
| 1.80 |
| S3 54.36 |
| L2 8.90 1.700 |
| 47.8 |
| S4 -220.65 |
| 0.15 |
| S5 46.30 |
| L3 4.00 1.834 |
| 37.3 |
| S6 83.28 |
| Z1 |
| S7 59.28 |
| L4 2.00 1.805 |
| 25.5 |
| S8 16.09 |
| 5.04 |
| S9 -59.80 |
| L5 2.00 1.609 |
| 59.2 |
| S10 28.34 |
| 0.50 |
| S11 23.44 |
| L6 8.00 1.699 |
| 30.1 |
| S12 -17.37 |
| L7 1.50 1.804 |
| 46.5 |
| S13 110.83 |
| Z2 |
| aperture |
| 1.30 |
| S14 63.48 |
| L8 2.00 1.834 |
| 37.3 |
| S15 -659.47 |
| Z3 |
| S16 32.68 |
| L9 4.79 1.661 |
| 57.0 |
| S17 -42.95 |
| 0.60 |
| S18 -29.12 |
| L10 12.32 1.593 |
| 35.5 |
| S19 43.26 |
| 3.27 |
| S20 - 229.66 |
| L11 3.80 1.543 |
| 46.9 |
| S21 -29.26 |
| 0.20 |
| S22 57.54 |
| L12 7.65 1.517 |
| 52.2 |
| S23 -24.09 |
| 1.54 |
| S24 -21.66 |
| L13 1.80 1.847 |
| 23.8 |
| S25 -68.41 |
| ______________________________________ |
| ZOOM DATA |
| f/No. EFL FVD Z1 Z2 Z3 BFL |
| ______________________________________ |
| 2.9 28.6 156.3 0.84 mm |
| 13.30 mm |
| 17.20 mm |
| 42.3 mm |
| mm mm |
| 3.2 48.0 161.8 10.32 9.14 11.89 47.8 |
| 3.5 55.0 167.0 18.36 5.95 7.03 53.0 |
| 4.0 87.0 174.3 28.70 1.78 .86 60.3 |
| ______________________________________ |
In the foregoing prescriptions, the front vertex distance (FVD) is calculated from a plane 6.5 mm in front of surfaces S1 when the lenses are focused to a magnification of 1:50.
The lenses set forth in Tables 1-III are so designed that the first and fourth groups move in the same direction for zooming. For simplicity of mechanical design of the zooming mechanism and to reduce the required size of the front group, the various lens groups move in fixed relation for focusing. Also the groups G1 and G4 move in fixed relation when zooming.
In the foregoing lens examples, the third group is in simplest form, a single element. In the given examples, the object side surface is convex, and on a much larger radius than the image side surface. ##EQU1## where RI is the radius of the image side surface and Ro is the radius of the object side surface.
FIGS. 2, 3, and 4 illustrate other embodiments of the invention where the third group at the aperture defining means is in the form of an air spaced doublet. FIG. 2 exemplifies the lens with the groups positioned toward its shorter EFL. The lens comprises elements L1-L6. Elements L1-L3 define a first positive group G1, elements L4-L8 define a second negative group G2. The aperture defining iris D is closely spaced to the third positive group G3 comprising elements L9 and L10. A fourth positive group is defined by elements L11-L16.
Group G1 has the same configuration as in examples I-III. Group G2 is again strongly negative, the forwardmost component is a doublet L4, L5 with the overall shape of a negative meniscus, followed by a biconcave element L6 and a positive doublet L7, L8. The third group G3 follows the aperture defining iris D and comprises a meniscus 19 air spaced from a biconvex element L10. Group G4 comprises a positive element L11, a doublet L12, L13, a biconvex doublet L14, L15, and a negative meniscus L16 concave to the object.
In the lens of FIG. 2, the third group G3 moves in fixed relation with the aperture defining iris D during variation in EFL. As the EFL is increased group G4 moves toward the object end, group G2 moves toward the image end, group G3 and the iris move in fixed relation toward the object, and group G1 moves toward the object.
The lens of FIG. 2 as scaled to an image frame of 24×36 mm for an EFL range of 25.5 mm to 124.0 mm is substantially described in Table IV.
| TABLE IV |
| ______________________________________ |
| Surface Axial Distance |
| Radius Between Surfaces |
| Lens Surface (mm) (mm) Nd |
| Vd |
| ______________________________________ |
| S1 143.67 |
| L1 3.00 1.805 |
| 25.5 |
| S2 45.42 |
| 0.03 |
| S3 45.12 |
| L2 13.33 1,476 |
| 70.4 |
| S4 -417.52 |
| 0.10 |
| S5 43.91 |
| L3 6.94 1.868 |
| 41.2 |
| S6 143.05 |
| Z1 |
| S7 99.50 |
| L4 2.00 1.860 |
| 22.8 |
| S8 -85.74 |
| L5 1.50 1.856 |
| 40.0 |
| S9 12.47 |
| 5.26 |
| S10 -41.14 |
| L6 2.00 1.847 |
| 44.5 |
| S11 36.97 |
| 0.20 |
| S12 23.01 |
| L7 6.81 1.711 |
| 26.7 |
| S13 -13.81 |
| L8 2.00 1.836 |
| 31.1 |
| S14 -91.05 |
| Z2 |
| aperture |
| 1.50 |
| S15 29.03 |
| L9 1.63 1.847 |
| 23.8 |
| S16 23.58 |
| 3.32 |
| S17 38.96 |
| L10 4.55 1.487 |
| 70.4 |
| S18 -40.98 |
| Z3 |
| S19 39.92 |
| L11 6.00 1.487 |
| 70.4 |
| S10 -109.09 |
| 0.50 |
| S21 32.42 |
| L12 8.48 1.465 |
| 65.8 |
| S22 -173.96 |
| L13 2.00 1.600 |
| 38.4 |
| S23 29.36 |
| 1.86 |
| S24 54.84 |
| L14 2.05 1.835 |
| 63.0 |
| S25 19.80 |
| L15 11.48 1.465 |
| 65.8 |
| S26 -20.07 |
| 0.79 |
| S27 -18.95 |
| L16 2.50 1.835 |
| 63.0 |
| S28 -34.13 |
| ______________________________________ |
| ZOOM DATA |
| f/No. EFL FVD Z1 Z2 Z3 BFL |
| ______________________________________ |
| 3.4 25.5 179.0 1.00 mm |
| 17.58 mm |
| 16.54 mm |
| 39.0 mm |
| mm mm |
| 4.1 40.0 179.6 9.53 11.05 13.26 51.0 |
| 4.2 85.0 185.4 28.96 5.68 1.44 54.5 |
| 4.6 124.0 190.9 34.31 1.25 1.53 59.0 |
| ______________________________________ |
Another lens embodying the invention is shown in FIG. 3 and comprises thirteen elements L1-L13 in four groups G1-G4. Group G1 comprises elements L1-L3 in the same positive configurations. Group G2 comprises elements L4-L7 in the same general negative configuration as FIG. 1. Group G3 is a positive doublet L8 and L9 in fixed relation to an aperture defining iris I. Group G4 comprises a positive element L10, a biconvex doublet L11, L12 and a negative meniscus concave to the object. Group G4 is of positive power.
Two examples of the lens as shown in FIG. 3 are set forth in Tables V and VI. Both lenses are scaled to an EFL range of 24.5 to 124 mm for a 24×36 mm image frame. In both lenses, the relative aperture varies from f/3.6 at the shorter EFL to F/4.7 at the larger EFL. In both of Tables V and VI, group G3 and the iris I remain stationary. Group G1 moves toward the object end as the EFL is increased, group G2 moves toward the image end, and group G4 moves toward the object end. Group G1 moves for focusing.
| TABLE V |
| __________________________________________________________________________ |
| Surface Radius |
| Axial Distance Between |
| Lens |
| Surface |
| (mm) Surfaces (mm) |
| Nd |
| Vd |
| __________________________________________________________________________ |
| S1 169.45 |
| L1 3.00 1.805 |
| 25.5 |
| S2 56.72 |
| 0.41 |
| S3 56.53 |
| L2 12.60 1.487 |
| 70.4 |
| S4 -605.21 |
| 0.10 |
| S5 54.35 |
| L3 6.9 1.834 |
| 37.3 |
| S6 151.66 |
| Z1 |
| S7 95.83 |
| L4 1.50 1.834 |
| 37.3 |
| S8 14.79 |
| 7.53 |
| S9 -65.44 |
| L5 2.00 1.835 |
| 63.0 |
| S10 42.84 |
| 0.20 |
| S11 27.06 |
| L6 15.72 1.741 |
| 27.8 |
| S12 -26.96 |
| L7 1.53 1.773 |
| 49.6 |
| S13 -508.18 |
| Z2 |
| aperture |
| S14 33.47 |
| L8 1.50 1.847 |
| 23.8 |
| S15 25.18 |
| 2.66 |
| S16 32.36 |
| L9 4.55 1.487 |
| 70.4 |
| S17 -58.18 |
| Z3 |
| S18 38.94 |
| L10 6.00 1.564 |
| 60.8 |
| S19 1862.11 |
| 10.93 |
| S20 94.60 |
| L11 2.00 1.850 |
| 32.2 |
| S21 22.04 |
| L12 11.50 1.471 |
| 67.3 |
| S22 -25.15 |
| S23 -21.83 |
| L13 2.00 1.620 |
| 60.3 |
| S24 -47.40 |
| __________________________________________________________________________ |
| ZOOM DATA |
| f/No. |
| EFL FVD Z1 Z2 Z3 BFL |
| __________________________________________________________________________ |
| 3.6 25.5 mm |
| 198.8 mm |
| 1.000 mm |
| 28.636 mm |
| 27.353 mm |
| 40.0 mm |
| 4.0 40.0 198.3 |
| 12.482 |
| 16.261 |
| 13.378 |
| 44.6 |
| 4.6 85.0 214.1 |
| 37.390 |
| 5.983 |
| 2.061 |
| 67.1 |
| 4.7 124.0 220.1 |
| 47.590 |
| .874 .700 69.3 |
| __________________________________________________________________________ |
| TABLE VI |
| __________________________________________________________________________ |
| Surface Radius |
| Axial Distance Between |
| Lens |
| Surface |
| (mm) Surfaces (mm) |
| Nd |
| Vd |
| __________________________________________________________________________ |
| S1 188.72 |
| L1 3.00 1.806 |
| 25.5 |
| S2 56.11 |
| 0.38 |
| S3 56.11 |
| L2 12.20 1.487 |
| 70.4 |
| S4 -608.85 |
| S5 55.24 |
| L3 6.94 1.834 |
| 37.3 |
| S6 172.29 |
| Z1 |
| S7 99.95 |
| L4 1.50 1.834 |
| 37.3 |
| S8 14.45 |
| 6.83 |
| S9 -63.20 |
| L5 2.00 1.835 |
| 43.0 |
| S10 42.33 |
| 0.20 |
| S11 26.50 |
| L6 14.48 1.761 |
| 26.8 |
| S12 -28.98 |
| L7 1.53 1.743 |
| 49.2 |
| S13 -699.54 |
| Z2 |
| aperture |
| 2.05 |
| S14 33.36 |
| L8 1.50 1.847 |
| 23.8 |
| S15 24.83 |
| 2.50 |
| S16 31.37 |
| L9 4.55 1.762 |
| 26.9 |
| S17 -56.74 |
| Z3 |
| S18 38.07 |
| L10 6.00 1.570 |
| 60.1 |
| S19 1365.55 |
| 11.47 |
| S20 88.72 |
| L11 2.00 1.850 |
| 32.2 |
| S21 21.05 |
| L12 11.50 1.471 |
| 67.3 |
| S22 -25.14 |
| 1.47 |
| S23 -21.79 |
| L13 2.00 1.591 |
| 63.0 |
| S24 -47.99 |
| __________________________________________________________________________ |
| ZOOM LENS |
| f/No. |
| EFL FVD Z1 Z2 Z3 BFL |
| __________________________________________________________________________ |
| 3.6 25.5 mm |
| 194.6 mm |
| 0.800 mm |
| 26.957 mm |
| 27.515 mm |
| 40.1 mm |
| 4.0 40.0 194.8 |
| 12.491 |
| 15.244 |
| 13.209 |
| 54.7 |
| 4.6 85.0 212.2 |
| 38.085 |
| 5.614 |
| 1.817 |
| 67.4 |
| 4.7 124.0 219.0 |
| 48.820 |
| 0.874 |
| 0.700 |
| 69.4 |
| __________________________________________________________________________ |
FIG. 4 exemplifies another lens form comprising four groups G1-G4. Group G1 comprises elements L1-L3. Group G2 comprises a negative doublet L4, L5 in the overall shape of a meniscus, a biconcave element L6, and a positive doublet L7, L8. Group G2 is of overall negative power. Group G3 comprises a positive doublet L9, L10 closely spaced behind aperture defining iris D. Group G4 comprises a biconvex element L11, a doublet L12, L13, and a triplet L14, L15, L16 of overall biconvex shape. Group G4 is of positive power.
Two lenses as shown in FIG. 4 are described in Table VII and Table VIII as scaled to an EFL range of 24.5 to 124 mm for an image frame of 24×36 mm.
| TABLE VII |
| ______________________________________ |
| Surface Axial Distance |
| Radius Between Surfaces |
| Lens Surface (mm) (mm) Nd |
| Vd |
| ______________________________________ |
| S1 131.80 |
| L1 3.00 1.805 25.5 |
| S2 45.99 |
| 0.40 |
| S3 45.95 |
| L2 13.33 1.487 70.4 |
| S4 -352.60 |
| 0.10 |
| S5 44.42 |
| L3 6.94 1.806 40.7 |
| S6 145.11 |
| Z1 |
| S7 138.87 |
| L4 2.00 1.847 23.8 |
| S8 -78.66 |
| L5 1.50 1.834 37.3 |
| S9 13.60 |
| 5.26 |
| S10 -53.44 |
| L6 2.00 1.835 43.0 |
| S11 29.14 |
| 0.20 |
| S12 20.88 |
| L7 10.12 1.717 29.5 |
| S13 -12.94 |
| L8 2.00 1.806 40.7 |
| S14 -475.25 |
| Z2 |
| aperture |
| 1.50 |
| S15 32.75 |
| L9 1.50 1.805 25.5 |
| S16 24.09 |
| 1.41 |
| S17 31.62 |
| L10 4.55 1.487 70.4 |
| S18 -44.76 |
| Z3 |
| S19 42.56 |
| L11 6.00 1.487 70.4 |
| S20 - 72.65 |
| 0.20 |
| S21 29.20 |
| L12 10.00 1.487 70.4 |
| S22 -42.37 |
| L13 2.00 1.548 45.8 |
| S23 24.84 |
| 2.00 |
| S24 50.95 |
| L14 2.05 1.786 43.9 |
| S25 18.30 |
| L15 11.00 1.511 60.5 |
| S26 -18.72 |
| L16 2.00 1.806 40.7 |
| S27 -50.49 |
| ______________________________________ |
| ZOOM DATA |
| f/No. |
| EFL FVD Z1 Z2 Z3 BFL |
| ______________________________________ |
| 3.8 25.5 185.0 1.000 11.408 37.476 38.5 |
| mm mm mm mm mm mm |
| 4.3 40.0 185.0 9.669 6.664 23.055 49.0 |
| 4.5 85.0 185.0 29.817 3.579 5.742 49.2 |
| 4.0 124.0 185.0 35.019 0.150 0.401 52.8 |
| ______________________________________ |
| TABLE VIII |
| ______________________________________ |
| Surface Axial Distance |
| Radius Between Surfaces |
| Lens Surface (mm) (mm) Nd |
| Vd |
| ______________________________________ |
| S1 142.69 |
| L1 3.00 1.805 25.5 |
| S2 46.13 |
| 0.40 |
| S3 46.01 |
| L2 13.33 1.487 70.4 |
| S4 -487.79 |
| 0.10 |
| S5 44.75 |
| L3 6.94 1.806 40.7 |
| S6 145.88 |
| Z1 |
| S7 106.19 |
| L4 2.00 1.847 23.8 |
| S8 -73.61 |
| L5 1.50 1.834 37.3 |
| S9 12.93 |
| 5.26 |
| S10 -49.58 |
| L6 2.00 1.835 43.0 |
| S11 39.03 |
| 0.20 |
| S12 21.94 |
| L7 14.07 1.717 29.5 |
| S13 -13.02 |
| L8 2.00 1.806 40.1 |
| S14 584.71 |
| Z2 |
| Aperture |
| 2.05 |
| S15 31.39 |
| L9 1.50 1.805 25.5 |
| S16 23.71 |
| 1.58 |
| S17 31.06 |
| L10 4.55 1.487 70.4 |
| S18 -51.85 |
| Z3 |
| S19 43.25 |
| L11 6.00 1.487 70.4 |
| S20 -70.85 |
| 0.20 |
| S21 27.36 |
| L12 10.00 1.487 70.4 |
| S22 -43.76 |
| L13 2.00 1.541 47.2 |
| S23 23.42 |
| 2.00 |
| S24 45.83 |
| L14 2.05 1.786 43.9 |
| S25 16.77 |
| L15 11.00 1.511 60.5 |
| S26 -18.30 |
| L16 2.00 1.806 40.7 |
| S27 -52.02 |
| ______________________________________ |
| ZOOM DATA |
| f/No. |
| EFL FVD Z1 Z2 Z3 BFL |
| ______________________________________ |
| 3.8 25.5 179.l 1.00 11.328 26.532 38.5 |
| mm mm mm mm mm mm |
| 4.3 40.0 183.3 9 993 6.959 15.013 50.6 |
| 4.5 85.0 194.9 30.520 3.333 3.717 56.6 |
| 4.6 l24.0 203.1 35.169 0.292 0.500 66.4 |
| ______________________________________ |
The lens of Table VII has a relative aperture varying from f/3.8 at the shorter EFL to f/4.6 at the larger EFL. The front vertex distance (FVD) of this lens does not change during zooming. As the FFL EFL is increased from the lower value, group G2 moves toward the image end, group G3 and iris D move in fixed relation toward the image end and group G4 moves toward the object end.
The lens of Table VIII has a relative aperture varying from f/3.8 to f/4.6 at the larger EFL. Here all four groups move during zooming. As the EFL is increased, group G1 moves toward the object end, group G2 moves toward the image end, group G3 and iris D first move toward the image end and then reverse and move toward the object end, and group G4 moves toward the object.
In the prescriptions of Tables IV-VIII, the front vertex distance (FVD) is calculated from a plane 5.00 mm in front of surfaces 51. In tables IV and VI the lenses are focused for a magnification of 1:40 and in tables V, VII and VIII the lenses are focused at infinity.
The power of the groups G1-G4 of the various lenses are set forth in Table IX as K1 -K4 respectively together with the geometric mean of the powers KG of the lens at the ERL extremities, and the zoom ratio ZR.
| TABLE IX |
| ______________________________________ |
| TABLE K1 K2 K3 |
| K4 |
| KG |
| ZR |
| ______________________________________ |
| I .0121 -.0498 .0114 .0224 .020 3.04 |
| II .0118 -.0512 .0129 .0220 .020 3.04 |
| III .0121 -.0556 .0145 .0223 .020 3.04 |
| IV .0143 -.0726 .0182 .0149 .0178 4.86 |
| V .0103 -.0521 .0156 .0110 .0178 4.86 |
| VI .0137 -.0748 .0177 .0186 .0178 4.86 |
| VII .0102 -.0528 .0159 .0115 .0178 4.86 |
| VIII .0129 -.0763 .0171 .0189 .0178 4.86 |
| ______________________________________ |
| ##STR1## |
| - where KL is the power of the lens at its longest EFL and KS i |
| the power of the lens at its shortest EFL. |
It will be noted from the foregoing examples that the power K3 of group G3 is substantially equal to or greater than the power K1 of the front group G1. Also K3 is substantially equal to or less than the geometric mean power KG of the lens at the extremes of its EFL range.
The power K3 of group G3 as shown above bears certain relationships to other parameters of the lens:
1.2>(K3 /KG)>0.4
0.006>(K3 /ZR)>0.003
0.25>(K3 /KG ZR)>0.15
The third group G3 may be placed on either side of the iris; however, in most cases to permit movement of the other groups to provide the smallest FVD, it will be very closely spaced to the image side of the iris.
While preferred embodiments of the invention have been described, alternate embodiments, as well as other embodiments of the invention may occur to those skilled in the art. Accordingly, the appended claims are intended to encompass all modifications and embodiments of the invention which do not depart from the spirit and scope of the invention.
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| Jul 09 2008 | Vivitar Corporation | SILVER POINT FINANCE, LLC, AS COLLATERAL AGENT | GRANT OF SECURITY INTEREST | 021230 | /0062 |
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