Abstract

The unique optical system of the folding single-lens-reflex viewfinder used in the Polaroid SX-70 Land camera has required novel approaches to design and manufacture. The camera uses an unusual short-barrel taking lens with front-element focus, two plane mirrors, an eccentric reflective Fresnel focus screen, an aspheric aperture element, an aspheric concave mirror, and an aspheric eye lens. All the viewing components are tilted or decentered, and two aspheres are not figures of revolution. Beginning with J. G. Baker’s computer design, special technology has been needed for producing millions of replicas of this system and controlling their quality.

© 1982 Optical Society of America

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References

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  1. E. H. Land, Photogr. Sci. Eng. 16, 247 (1972).
  2. E. H. Land, Photogr. J. 114, 338 (1974).
  3. E. H. Land, H. G. Rogers, V. K. Walworth, Neblette’s Handbook of Photography and Reprography (Van Nostrand Reinhold, New York, 1977), Chap. 12.
  4. J. G. Baker, U.S. Patent3,695,750 (1972).
  5. Advertisement, Sci. Am. 231 (6), 84 (1974).
  6. E. H. Land, U.S. Patent3,672,281 (1972).
  7. J. G. Baker, J. Opt. Soc. Am. 62, 1403A (1972).
  8. J. G. Baker, U.S. Patent3,678,831 (1972).
  9. Advertisement, Sci. Am. 232 (1), 68 (1975).
  10. Life 73 (17), 42 (1972).
  11. W. T. Plummer, U.S. Patent3,836,931 (1974).
  12. W. T. Plummer, J. Opt. Soc. Am. 62, 1403A (1972).
  13. J. G. Baker, U.S. Patent3,783,764 (1974).
  14. J. G. Baker, U.S. Patent3,860,940 (1975).
  15. W. T. Plummer, U.S. Patent3,735,685 (1973).
  16. W. T. Plummer, U.S. Patent4,006,971 (1977).
  17. W. T. Plummer, U.S. Patent3,718,078 (1973).
  18. W. T. Plummer, Appl. Opt. 14, 2762 (1975).
    [CrossRef] [PubMed]
  19. R. F. Weeks, V. E. Ford, N. Gold, S. Haskell, J. Opt. Soc. Am. 62, 1391A (1972).
  20. N. Gold, J. Opt. Soc. Am. 62, 1391A (1972).
  21. W. T. Plummer, U. W. Salomon, L. K. M. Ting, U.S. Patent3,761,179 (1973).
  22. W. T. Plummer, Appl. Opt. 15, 805 (1976).
    [CrossRef] [PubMed]
  23. N. Gold, W. T. Plummer, U.S. Patent3,904,294 (1975).
  24. W. T. Plummer, Appl. Opt. 16, 1914 (1977).
    [CrossRef] [PubMed]
  25. N. P. Patterson, R. Tousey, W. A. Delamere, Appl. Opt. 16, 922 (1977).
    [PubMed]

1977 (2)

1976 (1)

1975 (2)

Advertisement, Sci. Am. 232 (1), 68 (1975).

W. T. Plummer, Appl. Opt. 14, 2762 (1975).
[CrossRef] [PubMed]

1974 (2)

E. H. Land, Photogr. J. 114, 338 (1974).

Advertisement, Sci. Am. 231 (6), 84 (1974).

1972 (6)

J. G. Baker, J. Opt. Soc. Am. 62, 1403A (1972).

E. H. Land, Photogr. Sci. Eng. 16, 247 (1972).

Life 73 (17), 42 (1972).

W. T. Plummer, J. Opt. Soc. Am. 62, 1403A (1972).

R. F. Weeks, V. E. Ford, N. Gold, S. Haskell, J. Opt. Soc. Am. 62, 1391A (1972).

N. Gold, J. Opt. Soc. Am. 62, 1391A (1972).

Baker, J. G.

J. G. Baker, J. Opt. Soc. Am. 62, 1403A (1972).

J. G. Baker, U.S. Patent3,695,750 (1972).

J. G. Baker, U.S. Patent3,783,764 (1974).

J. G. Baker, U.S. Patent3,678,831 (1972).

J. G. Baker, U.S. Patent3,860,940 (1975).

Delamere, W. A.

Ford, V. E.

R. F. Weeks, V. E. Ford, N. Gold, S. Haskell, J. Opt. Soc. Am. 62, 1391A (1972).

Gold, N.

R. F. Weeks, V. E. Ford, N. Gold, S. Haskell, J. Opt. Soc. Am. 62, 1391A (1972).

N. Gold, J. Opt. Soc. Am. 62, 1391A (1972).

N. Gold, W. T. Plummer, U.S. Patent3,904,294 (1975).

Haskell, S.

R. F. Weeks, V. E. Ford, N. Gold, S. Haskell, J. Opt. Soc. Am. 62, 1391A (1972).

Land, E. H.

E. H. Land, Photogr. J. 114, 338 (1974).

E. H. Land, Photogr. Sci. Eng. 16, 247 (1972).

E. H. Land, U.S. Patent3,672,281 (1972).

E. H. Land, H. G. Rogers, V. K. Walworth, Neblette’s Handbook of Photography and Reprography (Van Nostrand Reinhold, New York, 1977), Chap. 12.

Patterson, N. P.

Plummer, W. T.

W. T. Plummer, Appl. Opt. 16, 1914 (1977).
[CrossRef] [PubMed]

W. T. Plummer, Appl. Opt. 15, 805 (1976).
[CrossRef] [PubMed]

W. T. Plummer, Appl. Opt. 14, 2762 (1975).
[CrossRef] [PubMed]

W. T. Plummer, J. Opt. Soc. Am. 62, 1403A (1972).

N. Gold, W. T. Plummer, U.S. Patent3,904,294 (1975).

W. T. Plummer, U.S. Patent4,006,971 (1977).

W. T. Plummer, U. W. Salomon, L. K. M. Ting, U.S. Patent3,761,179 (1973).

W. T. Plummer, U.S. Patent3,718,078 (1973).

W. T. Plummer, U.S. Patent3,836,931 (1974).

W. T. Plummer, U.S. Patent3,735,685 (1973).

Rogers, H. G.

E. H. Land, H. G. Rogers, V. K. Walworth, Neblette’s Handbook of Photography and Reprography (Van Nostrand Reinhold, New York, 1977), Chap. 12.

Salomon, U. W.

W. T. Plummer, U. W. Salomon, L. K. M. Ting, U.S. Patent3,761,179 (1973).

Ting, L. K. M.

W. T. Plummer, U. W. Salomon, L. K. M. Ting, U.S. Patent3,761,179 (1973).

Tousey, R.

Walworth, V. K.

E. H. Land, H. G. Rogers, V. K. Walworth, Neblette’s Handbook of Photography and Reprography (Van Nostrand Reinhold, New York, 1977), Chap. 12.

Weeks, R. F.

R. F. Weeks, V. E. Ford, N. Gold, S. Haskell, J. Opt. Soc. Am. 62, 1391A (1972).

Appl. Opt. (4)

J. Opt. Soc. Am. (4)

R. F. Weeks, V. E. Ford, N. Gold, S. Haskell, J. Opt. Soc. Am. 62, 1391A (1972).

N. Gold, J. Opt. Soc. Am. 62, 1391A (1972).

W. T. Plummer, J. Opt. Soc. Am. 62, 1403A (1972).

J. G. Baker, J. Opt. Soc. Am. 62, 1403A (1972).

Life (1)

Life 73 (17), 42 (1972).

Photogr. J. (1)

E. H. Land, Photogr. J. 114, 338 (1974).

Photogr. Sci. Eng. (1)

E. H. Land, Photogr. Sci. Eng. 16, 247 (1972).

Sci. Am. (2)

Advertisement, Sci. Am. 232 (1), 68 (1975).

Advertisement, Sci. Am. 231 (6), 84 (1974).

Other (12)

E. H. Land, U.S. Patent3,672,281 (1972).

E. H. Land, H. G. Rogers, V. K. Walworth, Neblette’s Handbook of Photography and Reprography (Van Nostrand Reinhold, New York, 1977), Chap. 12.

J. G. Baker, U.S. Patent3,695,750 (1972).

J. G. Baker, U.S. Patent3,678,831 (1972).

J. G. Baker, U.S. Patent3,783,764 (1974).

J. G. Baker, U.S. Patent3,860,940 (1975).

W. T. Plummer, U.S. Patent3,735,685 (1973).

W. T. Plummer, U.S. Patent4,006,971 (1977).

W. T. Plummer, U.S. Patent3,718,078 (1973).

W. T. Plummer, U. W. Salomon, L. K. M. Ting, U.S. Patent3,761,179 (1973).

W. T. Plummer, U.S. Patent3,836,931 (1974).

N. Gold, W. T. Plummer, U.S. Patent3,904,294 (1975).

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Figures (14)

Fig. 1
Fig. 1

Cutaway camera shows how the optical system is folded by a plane mirror for compactness.

Fig. 2
Fig. 2

Path of light from a centered bright object is made visible with smoke (photograph courtesy of Ref. 3).

Fig. 3
Fig. 3

Diagram of route from the taking lens A to the plane mirror B, reflective focus screen C, aperture stop and aspheric corrector plate D, concave mirror E, tilted aerial image F, eye lens G, and eye H.

Fig. 4
Fig. 4

Demonstration aspheric lens formed by tilting a water-filled flat plastic box covered with a stretched film of kitchen wrap. This shape does not have rotational symmetry (photo. courtesy of Ref. 9).

Fig. 5
Fig. 5

Cut section showing detail of the four-element glass taking lens. The first element travels on square-sectioned screw threads to focus.

Fig. 6
Fig. 6

Reflective focus screen acts as a concave mirror to image a lamp, representing the taking lens aperture, onto a piece of paper, standing in for the viewfinder aperture stop.

Fig. 7
Fig. 7

Computer drawing of aspheric surface used at the aperture stop to control coma, spherical aberration, and astigmatism. The circle is 4.75-mm diam.

Fig. 8
Fig. 8

Pattern of coma produced by putting surface of Fig. 7 in the path of an expanded laser beam converging slowly to a point focus.

Fig. 9
Fig. 9

Foucault tester for aspheric concave mirrors, consisting of a lamp A, microscope objective B, pinhole C, the mirror to be tested D, a compensating asphere E, occulting spot F, plane mirror G, and field lens H. When viewed from above, defective areas of the concave mirror appear bright on a dark background. Note that C and F are placed on the symmetry axis of aspheres D and E, so this works over the entire surface of the concave mirror.

Fig. 10
Fig. 10

Computer drawing of aspheric surface used on the eye lens to control focus and astigmatism variations over the field. The area shown is 20.3-mm square.

Fig. 11
Fig. 11

Molded eye lens and concave mirror are retained in individual molded housings with mechanical features to locate them accurately when the camera is opened.

Fig. 12
Fig. 12

Use of two plane mirrors enables us to match path lengths used for viewing and for exposing the film. The viewing mirror is slightly longer to allow space for the second reflection.

Fig. 13
Fig. 13

Diagram of automatic apparatus used for testing all the plane mirrors for overall flatness and for local irregularity.

Fig. 14
Fig. 14

Camera of Fig. 1 collapsed for portability.

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