Cinematographer
Ich kalibriere meine Belichtungsmessung ausschliesslich nach T-Stops, da sie mir die exakte Lichtmenge garantieren, die tatsaechlich den Sensor erreicht.
Measure of the actual light transmission of a lens accounting for all optical losses. More precise than F-stop for film production.
T-Stop (Light Transmission)
The T-stop is the actual light transmission ratio of a lens under real-world conditions. Unlike the F-stop, which is a geometric calculation, the T-stop measures the exact amount of light that the lens actually transmits to the sensor or film.
Technical Fundamentals
Measuring T-stops
T-stops are measured photometrically using calibrated light sensors under standardized conditions:
- Standard Illumination: 5600K daylight
- Spectral Range: Full visible spectrum
- Measurement Method: Integral light transmission measurement
- Calibration Standard: SMPTE / ISO 518 for cinematography
T-Stop vs. F-Stop
| Aspect | F-Stop | T-Stop |
|---|---|---|
| Calculation | Geometric (Focal length/Diameter) | Photometrically measured |
| Accuracy | Theoretical | Practical |
| Glass Losses | Not considered | Fully considered |
| Usage | Photography | Film production |
| Lens Marking | Standard photo lenses | Cinema lenses |
Practical Relevance
A lens with f/2.0 might actually be T/2.3 if glass elements and coatings absorb 15% of the light. When changing lenses within a scene, T-stops guarantee identical exposure without additional testing.
From the crafts
Perspectives
Director
Die Konsistenz von T-Stops ermoeglicht mir praezise visuelle Kontinuitaet zwischen verschiedenen Kamerasetups derselben Szene.
Producer
T-Stop-kalibrierte Objektive kosten 40 Prozent mehr, reduzieren aber Drehzeit durch wegfallende Belichtungstests um 15 Minuten pro Setup.
More in the lexikon
Related terms
Test your knowledge
Quiz
1. Zu welchem Department gehört „T-Stop / T-Blende"?
2. Wie viele verschiedene Fachperspektiven bietet dieser Eintrag?