Study of Relationship between Lux and F-Stop Illuminance for Three-Point Lighting Photograph Recording

Abstract

This research was to study the relationship between Lux and f-stop illuminance units for photography recording by using incident light measuring and calculating based on Lambert Cosine Law under the three-point light theory. The results found that the first position lamp that was main lamp (1,000W Fresnel Tungsten-Halogen lens) had a measurement error with the calculation of the light intensity in Lux and f-stop units equal 10.9% and 0.71 % respectively, the second position lamp (650W Fresnel Tungsten-Halogen lens) had a measurement error with the calculation of the light intensity in Lux and f-stop units equal 19.3% and 1.25% respectively and the third position lamp (2,000W Fresnel Tungsten-Halogen lens) had a measurement error with the calculation of the light intensity in Lux and f-stop units equal 11.1% and 0.12 % respectively.

                The inconstancies were caused by holding the tool by hand instead of using a fixed stand while measuring and the flickering of the lamps. The Study revealed that the camera menu currently does not provide Lux information and the light manufacturers only give information in Lux and Foot-candle units. Therefore, it is the gaffer’s responsibility to decide the amount of illumination suitable for recording the subject/person without using excessive brightness. This approach can also save energy and indirectly make it more cost effective for television and film lighting.