Disclosed is an optical design for a variable focal length lens of large effective aperture which is focusable over an extended range including the "macro" range and is provided with a high degree of correction.
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1. An optical system for a variable focal length lens of large effective aperture, which is focusable over an extended range, having substantially the following specification:
wherein the first column lists the lens elements numerically starting at the ray entrance side of the system; the second column lists the respective base radii R1 to R32 ; the third column lists the thicknesses T1 -T16 of the respective elements; the fourth column lists the axial spacings S1 to S17 between the respective elements, and stop, and the image plane; and the fifth and sixth columns respectively list the index of refraction for the Sodium D line ND and the dispersive index V of the optical materials of the respective elements. 2. An optical system for a variable focal length lens of large effective aperture, which is focusable over an extended range, having substantially the following specification:
elements. 3. An optical system for a variable focal length lens which is focusable over an extended range defined by a first range portion for normal object distances and a second range portion for shorter object distances, said optical system comprising: a focusing component including first and second elements arranged into a positive doublet, and a positive third element; a variator component including a negative fourth element, and fifth and sixth elements arranged into a negative doublet; a compensator component including seventh and eighth elements arranged into a positive doublet, and a positive ninth element; a collimator component including a negative tenth element, and a positive eleventh element; and a prime lens component including a positive twelfth element, a negative thirteenth element, fourteenth and fifteenth elements arranged into a positive doublet, and a positive sixteenth element; all of said elements being located on a common optical axis and following one another in the order set forth; said focusing component being movable for focusing said optical system over said first range portion; said variator component being movable for variation of the focal length of said optical system; said compensator component being movable relative to said variator component for focusing of said optical system over said second range portion. 4. An optical system for a variable focal length lens which is focusable over an extended range defined by a first range portion for normal object distances and a second range portion for shorter object distances, said optical system comprising: a focusing component including first and second elements arranged into a positive doublet, said first element being a negative meniscus and said second element being biconvex, and a positive meniscus third element; a variator component including a negative meniscus fourth element, and fifth and sixth elements arranged into a negative doublet, said fifth element being biconcave and said sixth element being a positive meniscus; a compensator component including seventh and eighth elements arranged into a positive doublet, said seventh element being a negative meniscus and said eighth element being biconvex, and a positive meniscus ninth element; a collimator component including a negative biconcave tenth element, and a positive meniscus eleventh element; and a prime lens component including a positive biconvex twelfth element, a negative biconcave thirteenth element, fourteenth and fifteenth elements arranged into a positive doublet, said fourteenth element being a negative meniscus and said fifteenth element being biconvex, and a positive sixteenth element; all of said elements being located on a common optical axis and following one another in the order set forth; said focusing component being movable for focusing said optical system over said first range portion; said variator component being movable for variation of the focal length of said optical system; said compensator component being movable relative to said variator component for focusing of said optical system over said second range portion. 5. An optical system for a variable focal length lens which is focusable over an extended range defined by a first range portion for normal object distances and a second range portion for shorter object distances, said optical system comprising: a focusing component including first and second elements arranged into a positive doublet, and a positive third element; a variator component including a negative fourth element, and fifth and sixth elements arranged into a negative doublet; a compensator component including seventh and eighth elements arranged into a positive doublet, and a positive ninth element; a collimator component including a negative tenth element, and a positive eleventh element; and a prime lens component including a positive twelfth element, a negative thirteenth element, fourteenth and fifteenth elements arranged into a positive doublet, and a positive sixteenth element; all of said elements being located on a common optical axis and following one another in the order set forth. 6. An optical system for a variable focal length lens which is focusable over an extended range defined by a first range portion for normal object distances and a second range portion for shorter object distances, said optical system comprising: a focusing component including first and second elements arranged into a positive doublet, said first element being a negative meniscus and said second element being biconvex, and a positive meniscus third element; a variator component including a negative meniscus fourth element, and fifth and sixth elements arranged into a negative doublet, said fifth element being biconcave and said sixth element being a positive meniscus; a compensator component including seventh and eighth elements arranged into a positive doublet, said seventh element being a negative meniscus and said eighth element being biconvex, and a positive meniscus ninth element; a collimator component including a negative biconcave tenth element, and a positive meniscus eleventh element; and a prime lens component including a positive biconvex twelfth element, a negative biconcave thirteenth element, fourteenth and fifteenth elements arranged into a positive doublet, said fourteenth element being a negative meniscus and said fifteenth element being biconvex, and a positive sixteenth element; all of said elements being located on a common optical axis and following one another in the order set forth. |
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This application is a continuation-in-part of Ser. No. 625,965 filed Oct. 28, 1975, and now abandoned.
FIGS. 4A to 4H are graphical representations of the various aberrations of the lens system having the design data given in Table 2 when in the wide angle mode. a zoom range.
The lens includes a positive first component C1, starting at the ray entrance side of the optical system, which component is adjustable axially through a short distance for focusing of the optical system throughout a range of approximately 1 meter to infinity. Component C2 is a variator or negative component variable along the axis of the optical system for varying the equivalent focal length of the objective. The equivalent focal length is variable over greater than a six-to-one range of magnification while maintaining a high degree of optical correction for a large aperture of at least f/1.2 throughout the range. Component C3 is a component adjustable axially upon axial adjustment of the variator, to function as a compensator for correcting aberrations caused by varying the focal length of the optical system, and being independently adjustable for focusing of the optical system in the macro range. Component C4 is a fixed lens member for further collimating rays exiting the compensator component C3. Rear component C5 is a prime lens group forming an afocal system with the earlier described components.
The front component C1, comprises a front biconvex cemented doublet L1, L2, and a rear singlet L3, predominately convex forwardly and spaced close to the doublet L1, L2. Air spaced from the rear of the singlet L3 and adjustable relative thereto is component C2 which comprises a front negative meniscus singlet L4 convex forwardly and a rear biconcave, cemented doublet L5, L6 predominately concave forwardly. The doublet has collective internal contact surfaces R10, R11.
Component C3 is variably air spaced relative to component C2 and the following component C4. Component C3 comprises a positive doublet L7, L8 predominately convex rearwardly. During a zooming or focal length varying operation, the component C3 is moved axially at a rate proportional to the rate of movement of component C2. However, for macro focusing action, the driver (not shown) of the components C2 and C3 by which axial adjustment thereof is accomplished is disconnected. from component C2 to cause that component to remain stationary while component C3 is adjusted axially for focusing.
Component C4 is fixed ahead of the stop of the optical system and comprises a front negative meniscus singlet L10 and a rear positive meniscus singlet L11 which together form a substantially afocal system cooperating with the rear prime lens system C5.
Component C5 comprises a front biconvex singlet L12, spaced somewhat from a negative element L13. A doublet of elements L14 and L15 is arranged between element L13 and rear element L16 which is a singlet predominately convex forwardly.
The element elements L1 to L16 have spherical surfaces or radii of curvature R1 to R32, axial thicknesses T1 to T15 and axial separations S1 to S14. The separations at S11 and S12 are sufficient to provide clearance for an aperture adjusting stop.
A preferred embodiment of the macro focusing, large aperture, zoom lens of the invention is constructed according to the table following wherein dimensions are as set forth and the refractive indices for the sodium D line and the Abbe dispersion numbers are respectively designated at ND and V.
| TABLE 1 |
| __________________________________________________________________________ |
| SYSTEM EFL HALF ANGLE OF FIELD |
| at W/A = 7.22mm (.2835 in.) |
| 27.36° |
| at T/P = 43.86mm (1.7268 in.) |
| 4.46° |
| at MID = 19.25mm (.7579 in.) |
| 10.02° |
| LENS |
| RADII (mm.) |
| THICKNESS (mm) |
| SPACINGS (mm) |
| ND |
| V |
| __________________________________________________________________________ |
| 1 R1 = 166.0901 |
| R2 = -45.7200 |
| T1 = 1.702 1.755 |
| 27.6 |
| S1 = 0 |
| 2 R3 = 45.7200 |
| R4 = 233.4001 |
| T2 = 11.430 1.623 |
| 56.9 |
| S2 = .1016 |
| 3 R5 = 50.3428 |
| R6 = -301.7523 |
| T3 = 7.112 1.651 |
| 56.2 |
| S3 = 1.4910 at W/A |
| 27.1882 at T/P |
| 17.7851 at MID |
| 4 R7 = 70.3580 |
| R8 = -16.8656 |
| T4 = 0.800 1.639 |
| 55.4 |
| S4 = 6.584 |
| 5 R9 = -24.0030 |
| R10 = -19.1008 |
| T5 = 0.800 1.620 |
| 60.3 |
| S5 = 0 |
| 6 R11 = 19.1008 |
| R12 = -59.9948 |
| T6 = 3.556 1.785 |
| 25.7 |
| S6 = 38.3210 at W/A |
| 2.7508 at T/P |
| 17.1018 at MID |
| 7 R13 = 53.9750 |
| R14 = -21.3106 |
| T7 = 0.800 1.805 |
| 25.4 |
| S7 = 0 |
| 8 R15 = 21.3106 |
| R16 = 31.6230 |
| T8 = 5.121 1.640 |
| 60.2 |
| S8 = .1016 |
| 9 R17 = 23.2664 |
| R18 = -101.5237 |
| T9 = 3.150 1.691 |
| 54.8 |
| S9 = 1.7348 at W/A |
| 11.6103 at T/P |
| 6.6573 at MID |
| 10 R19 = -45.5168 |
| R20 = -12.8016 |
| T10 = 0.711 1.691 |
| 54.8 |
| S10 = 2.2758 |
| 11 R21 = 14.6431 |
| R22 = -27.4320 |
| T11 = 2.091 1.805 |
| 25.4 |
| S11 = 10.668 |
| STOP |
| S12 = 3.556 |
| 12 R23 = 17.2720 |
| R24 = 30.4292 |
| T12 = 3.226 1.774 |
| 44.8 |
| S13 = 1.6764 |
| 13 R25 = -19.3040 |
| R26 = -17.1196 |
| T13 = 0.711 1.805 |
| 25.4 |
| S14 = .8890 |
| 14 R27 = 173.1519 |
| R28 = -16.5100 |
| T14 = 4.496 1.805 |
| 25.4 |
| S15 = 0 |
| 15 R29 = 16.5100 |
| R30 = 21.8034 |
| T15 = 2.794 1.744 |
| 44.8 |
| S16 = .1270 |
| 16 R31 = 14.9758 |
| R32 = -424.1817 |
| T16 = 3.023 1.734 |
| 51.5 |
| S17 = 11.277 |
| BFL |
| __________________________________________________________________________ |
In the Table 1 above, the first column lists the lens elements numerically starting at the ray entrance side of the system. The second column lists the respective radii of the elements in millimeters. The third column lists the axial thickness T of the respective elements in millimeters. The fourth column lists in millimeters the axial spacings between the respective elements, and the nominal image plane. EFL is the effective focal length of the lens system at wide angle condition W/A, at telephone telephoto condition T/P, and at mid range condition MID. "One-half Angle of Field" is one half the angle between the continuation of the lens axis and a line from the nodal point of the lens to the most oblique point recorded on the film when considered at the above expressed conditions.
FIGS. 2A to 2H graphically represent various aberrations of the form of the optical system, as shown in FIG. 1 and having the design data recited in Table 1. FIG. 2A represents correction of the rays on axis. FIG. 2B represents off axis aberrations of rays passing from the zone of the film format and through the lens transversely and tangentially. FIG. 2C represents the aberrations of the rays passing from the corner of the film format through the lens tangentially and transversely. FIG. 2D represents the radial or longitudinal aberrations from the zone of the film format of rays entering the lens at 3 o'clock, while FIG. 2E represents similar aberrations from full field or corner rays. FIG. 2F represents distortion as a percentage of a "perfect" image. FIG. 2G represents the spherical aberrations by a full line and the offense-against-sine condition by the dotted line. FIG. 2H represents the curvature of field with tangential curvature being shown in full line and sagittal curvature being shown in dashed line.
FIGS. 3A to 3H graphically represent various aberrations of the optical system with the lens adjusted to the telephoto condition, as opposed to the wide angle condition as represented in FIGS. 2A to 2H. In FIGS. 2A to 2E and 3A to 3E, the solid line represents the aberrations of a light ray at 5893 A, the dotted line represents a light ray at 6563 A, and the dashed line a light ray at 4861 A.
The design data of another embodiment of the optical system is shown in Table 2 set forth hereinafter. This optical system has a similar construction to the system shown in FIG. 1. FIGS. 4A to 4H, and FIGS. 5A to 5H graphically represent various aberrations related to the form of the optical system as described in the data of Table 2. The graphs in FIGS. 4A to 4H relate to the wide angle condition of the optical system, while the graphs of FIGS. 5A to 5H relate to the telephoto condition. The aberrations are identified with respect to FIGS. 2A to 2H. TABLE 2 __________________________________________________________________________ SYSTEM EFL HALF ANGLE OF FIELD at W/A = 7.61mm (.2997 in.) 25.35° at T/P = 56.98mm (2.2433 in.) 3.31° at MID = 25.67mm (1.0105 in.) 7.58° LENS RADII (mm.) THICKNESS (mm.) SPACINGS (mm) ND V __________________________________________________________________________ 1 R1 = 240.7589 R2 = -51.1988 T1 = 1.6510 1.755 27.6 S1 = 0 2 R3 = 51.1988 R4 = 152.7810 T2 = 12.7000 1.620 60.4 S2 = .1016 3 R5 = 43.6880 R6 = -139.7000 T3 = 7.7978 1.651 55.9 S3 = 4.2875 at W/A 29.5554 at T/P 22.3952 at MID 4 R7 = 71.7550 R8 = -16.5100 T4 = .8128 1.639 55.4 S4 = 6.6294 5 R9 = -24.0030 R10 = -19.1008 T5 = .8382 1.620 60.4 S5 = 0 6 R11 = 19.1008 R12 = -59.9948 T6 = 3.5052 1.785 25.8 S6 = 38.4048 at W/A 2.5857 at T/P 14.2570 at MID 7 R13 = 58.9280 R14 = -21.7424 T7 = .8890 1.805 25.4 S7 = 0 8 R15 = 21.7424 R16 = 30.2260 T8 = 5.6388 1.641 60.1 S8 = .1016 9 R17 = 22.7203 R18 = 93.1672 T9 = 3.1496 1.691 54.9 S9 = 1.6002 at W/A 12.1514 at T/P 7.6403 at MID 10 R19 = -45.5168 R20 = -12.8016 T10 = .7112 1.691 54.9 S10 = 2.2352 11 R21 = 16.6431 R22 = -27.0256 T11 = 2.0574 1.805 25.4 S11 = 11.0490 STOP S12 = 3.5560 12 R23 = 18.0848 R24 = 32.8168 T12 = 3.6576 1.744 44.8 S13 = 1.6002 13 R25 = -21.9202 R26 T13 = .7112 1.805 25.4 S14 = .7336 14 R27 = 61.2140 R28 = -14.5288 T14 = 4.3180 1.805 25.4 S15 = 0 15 R29 = 14.5288 R30 = 26.9494 T15 = 3.2512 1.744 44.8 S16 = .1270 16 R31 = 14.7320 R32 = -463.9259 T16 = 2.5654 1.734 51.7 S17 = 11.4529 __________________________________________________________________________
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| 3972591, | Feb 01 1972 | Canon Kabushiki Kaisha | Greatly variable magnification zoom lens system of large aperture ratio |
| Executed on | Assignor | Assignee | Conveyance | Frame | Reel | Doc |
| Jan 23 1978 | Bell & Howell Company | (assignment on the face of the patent) | / | |||
| Sep 07 1983 | BELL & HOWELL COMPANY, AN ILL CORP MERGED INTO | BELL & HOWELL COMPANY A DE CORP | MERGER SEE DOCUMENT FOR DETAILS , EFFECTIVE MAY 6, 1977, DELAWARE | 004195 | /0168 | |
| Sep 07 1983 | DELAWARE BELL & HOWELL COMPANY, A DE CORP CHANGED TO | BELL & HOWELL COMPANY A DE CORP | MERGER SEE DOCUMENT FOR DETAILS , EFFECTIVE MAY 6, 1977, DELAWARE | 004195 | /0168 |
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