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Journal of the Society of Motion Picture Engineers ( Volume: 49, Issue: 2, August 1947)
[ACTIVE]

An Instrument for Photometric Calibration of Lens Iris Scales

Metadata

Publisher
SMPTE — White Plains, NY, USA
Doc Type
Journal Article
Content Type
Original Research
Abbreviated Title
J SMPE
Volume
49, No. 2, pp. 111–122
Abstract
An instrument for calibrating iris scales of photographic lenses is described. The iris scales are calibrated in T stops based on the photometric transmission parallel to the axis. This follows the procedure proposed by Daily.1 The new instrument employs measuring and comparison of optical paths which receive alternate light pulses from a single incandescent source. Calibrated attenuation is provided in the comparison beam so that the two systems may be balanced to give a null output from the photomultiplier cell which is used as a null detector. The null-balance principle makes the unit extremely stable and the sensitivity is sufficient to make accurate measurements on iris openings as small as 0.031 in., which corresponds to 1 in. T 32. Data are given on transmission of several lens types, and on the accuracy of the instrument, and a proposal is made for changing over to the new system.
Publication Date
1947-08-01
DOI
10.5594/J17822
ISSN
Print: 0097-5834
Link
https://doi.org/10.5594/J17822
Author(s)
M. G. Townsley
Copyright
© 1947 Society of Motion Picture and Television Engineers, Inc.

Bibliographic Reference(s)

  • The Photronic Photographic Exposure Meter [Active]
  • A Lens Calibrating System [Active]
  • Citation on the Work OF Charles J. Kunz, Herbert E. Goldberg, and Charles E. Ives [Active]
  • 2 Gardner Irvine C. : “Compensation of the Aperture Ratio Markings of Photographic Lenses for Absorption, Reflection, and Vignetting Losses” , (presented, Optical Society of America Fall Meeting, 1947 ); J. Soc. Mot. Pict. Eng., 49, 2 (Aug. 1947), p. 96. EXTERNAL
  • 5 Back F. G. : “A Simplified Method for Precision Calibration of Effective f Stops” , J. Soc. Mot. Pict. Eng. , 49 , 2 (Aug. 1947 ), p. 122 . EXTERNAL
  • 6 Murray A. E. : “The Photometric Calibration of Lens Apertures” , J. Soc. Mot. Pict. Eng. , 47 , 2 (Aug. 1946 ), p. 142 . EXTERNAL
  • 7 Silvertooth E. W. : “Stop Calibration of Photographic Objectives” , J. Soc. Mot. Pict. Eng. , 39 , 2 (Aug. 1942 ), p. 119 . EXTERNAL
  • 8 Carpenter R. O'B. : “New Light-Balancing Circuit for the Non-Recording Densitometer” , J. Opt. Soc. Am. , 36 , 11 (Nov. 1946 ), p. 676 . EXTERNAL
  • 9 Hardy A. C. Perrin F. H. , “Principles of Optics” , McGraw-Hill Book Co. , New York, N. Y. , 1932 , Chap. 19. EXTERNAL
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M. G. Townsley; An Instrument for Photometric Calibration of Lens Iris Scales, Journal of the Society of Motion Picture Engineers ( Volume: 49, Issue: 2, August 1947); SMPTE, 1947. Available at https://doi.org/10.5594/J17822
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M. G. Townsley; An Instrument for Photometric Calibration of Lens Iris Scales, Journal of the Society of Motion Picture Engineers ( Volume: 49, Issue: 2, August 1947); SMPTE, 1947. Available at https://doi.org/10.5594/J17822

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M. G. Townsley; An Instrument for Photometric Calibration of Lens Iris Scales, Journal of the Society of Motion Picture Engineers ( Volume: 49, Issue: 2, August 1947); SMPTE, 1947. Available at https://doi.org/10.5594/J17822
Snippet:
<span class="citation">M. G. Townsley; <cite>An Instrument for Photometric Calibration of Lens Iris Scales</cite>, Journal of the Society of Motion Picture Engineers ( Volume: 49, Issue: 2, August 1947); SMPTE, 1947. Available at <a href="https://doi.org/10.5594/J17822" target="_blank" rel="noopener">https://doi.org/10.5594/J17822</a></span>

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M. G. Townsley; An Instrument for Photometric Calibration of Lens Iris Scales, Journal of the Society of Motion Picture Engineers ( Volume: 49, Issue: 2, August 1947); SMPTE, 1947
doi: 10.5594/J17822
url: https://doi.org/10.5594/J17822
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<li>
M. G. Townsley; <cite id="bib-10-5594-j17822">An Instrument for Photometric Calibration of Lens Iris Scales</cite>, Journal of the Society of Motion Picture Engineers ( Volume: 49, Issue: 2, August 1947); SMPTE, 1947
<span class="doi">10.5594/J17822</span>
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