Transmission Apertures (T-Stops) for Taking Lenses
The geometrically defined relative apertures, f-stops, engraved on objective lenses, are quite imprecise as measurements of the amounts of light actually transmitted, especially for zoom lenses with their many glass-air interfaces. This can lead to errors in exposure as a consequence of reflection, absorption and other light losses within the objective. The problems and the needs for the standardization of true transmission stops are discussed. A photometric measuring method in accordance with the German standard draft DIN 19 010, sheet 2 (photoelectric exposure meters, automatic exposure adjustment in photographic cameras) is presented for discussion.
- Print ISSN
- 0361-4573
- Published
- 1974-03
- Content type
- Original Research
- DOI
- 10.5594/J08805
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