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Journal of the Society of Motion Picture Engineers ( Volume: 46, Issue: 5, May 1946)
[ACTIVE]

A Lens Calibrating System

Metadata

Publisher
SMPTE
Doc Type
Journal Article
Article Type
research-article
Abstract
This paper describes a method for the calibration of the effective f/stop value of a camera lens in terms of the light transmitted by the lens. Owing to light losses within a lens, the f/value determined in this manner will normally be numerically larger than the values obtained from the geometry of the lens. However, stop values based on transmission are of considerably greater value to a cameraman than values based on apertures. An interrupted, collimated beam of light falls on the entrance port of an integrating sphere. The lens to be calibrated is centered over the opening and the light output from the sphere measured through a stable a-c amplifier equipment. A calibration curve is then obtained for the equipment wherein metal plates with holes of known diameters are placed over the entrance of the sphere in place of the lens. The effective aperture of the lens is then defined as the size of opening which will pass the same total amount of light as the lens under calibration. This method avoids the use of secondary standards and should be capable of duplication in any laboratory.
Publication Date
1946-05-01
DOI
10.5594/J11831
Link
https://doi.org/10.5594/J11831
Author(s)
C. R. Daily
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C. R. Daily; A Lens Calibrating System, Journal of the Society of Motion Picture Engineers ( Volume: 46, Issue: 5, May 1946); SMPTE, 1946. Available at https://doi.org/10.5594/J11831
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C. R. Daily; A Lens Calibrating System, Journal of the Society of Motion Picture Engineers ( Volume: 46, Issue: 5, May 1946); SMPTE, 1946. Available at https://doi.org/10.5594/J11831

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C. R. Daily; A Lens Calibrating System, Journal of the Society of Motion Picture Engineers ( Volume: 46, Issue: 5, May 1946); SMPTE, 1946. Available at https://doi.org/10.5594/J11831
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<span class="citation">C. R. Daily; <cite>A Lens Calibrating System</cite>, Journal of the Society of Motion Picture Engineers ( Volume: 46, Issue: 5, May 1946); SMPTE, 1946. Available at <a href="https://doi.org/10.5594/J11831" target="_blank" rel="noopener">https://doi.org/10.5594/J11831</a></span>

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Preview:
C. R. Daily; A Lens Calibrating System, Journal of the Society of Motion Picture Engineers ( Volume: 46, Issue: 5, May 1946); SMPTE, 1946
doi: 10.5594/J11831
url: https://doi.org/10.5594/J11831
Snippet:
<li>
C. R. Daily; <cite id="bib-10-5594-j11831">A Lens Calibrating System</cite>, Journal of the Society of Motion Picture Engineers ( Volume: 46, Issue: 5, May 1946); SMPTE, 1946
<span class="doi">10.5594/J11831</span>
</li>