API Registry JSON CSV exports Resources
Theme

Choose how MSRBot.io looks on this device.

Auto (match system) Light mode Dark mode

Preference is stored in this browser only.

Journal of the Society of Motion Picture Engineers ( Volume: 51, Issue: 3, September 1948)
[ACTIVE]

Errors in Calibration of the f Number

Metadata

Publisher
SMPTE
Doc Type
Journal Article
Article Type
research-article
Abstract
The present system of marking the diaphragm stops in terms of the geometric f number is subject to serious deficiencies so far as uniform performance for lenses set at the same marked stop opening is concerned. Decisions regarding the proper exposure time to use at a selected stop opening may be in error by ± 10 per cent for a lens whose surfaces do not have antireflection coatings, and by even greater amounts for a lens whose surfaces do have antireflection coatings. These errors arise from differences in the reflection and absorption losses in the lens elements themselves, departures of the measured from the nominal focal length, and departures of the measured diaphragm openings from the nominal diaphragm openings. A method is described whereby a lens can be calibrated by a light meter in terms of an ideal lens so that the variation in axial illumination in the focal plane need not exceed ± 2 per cent in using different lenses set to the same calibrated stop opening.
Publication Date
1948-09-01
DOI
10.5594/J11752
Link
https://doi.org/10.5594/J11752
Author(s)
Francis E. Washer
Source Data (JSON)

Full registry record with provenance metadata. Open directly: /api/doc/10.5594-J11752.json

Reference this Doc

Plain text (ISO 690 compliant)

Preview:
Francis E. Washer; Errors in Calibration of the f Number, Journal of the Society of Motion Picture Engineers ( Volume: 51, Issue: 3, September 1948); SMPTE, 1948. Available at https://doi.org/10.5594/J11752
Snippet:
Francis E. Washer; Errors in Calibration of the f Number, Journal of the Society of Motion Picture Engineers ( Volume: 51, Issue: 3, September 1948); SMPTE, 1948. Available at https://doi.org/10.5594/J11752

HTML (ISO 690 compliant)

Preview:
Francis E. Washer; Errors in Calibration of the f Number, Journal of the Society of Motion Picture Engineers ( Volume: 51, Issue: 3, September 1948); SMPTE, 1948. Available at https://doi.org/10.5594/J11752
Snippet:
<span class="citation">Francis E. Washer; <cite>Errors in Calibration of the f Number</cite>, Journal of the Society of Motion Picture Engineers ( Volume: 51, Issue: 3, September 1948); SMPTE, 1948. Available at <a href="https://doi.org/10.5594/J11752" target="_blank" rel="noopener">https://doi.org/10.5594/J11752</a></span>

SMPTE Icon SMPTE's HTML Pub

Preview:
Francis E. Washer; Errors in Calibration of the f Number, Journal of the Society of Motion Picture Engineers ( Volume: 51, Issue: 3, September 1948); SMPTE, 1948
doi: 10.5594/J11752
url: https://doi.org/10.5594/J11752
Snippet:
<li>
Francis E. Washer; <cite id="bib-10-5594-j11752">Errors in Calibration of the f Number</cite>, Journal of the Society of Motion Picture Engineers ( Volume: 51, Issue: 3, September 1948); SMPTE, 1948
<span class="doi">10.5594/J11752</span>
</li>