Talk:Lighting ratio

Wrong ratios, wrong units.,
The lighting ratio is not the ratio of the key to the fill but the ratio of light in the highlights (which is the key and the fill) to that in the shadows (which is the fill only.) So the correct ratio is (K+F):F. not K:F. Also, light is properly measured in the international unit of Lux, not the obsolete (and purely American) one of Foot Candles.

The given formula of K+F:F can never produce a lighting Ratio of 1:1; therefor, the proper metering to determine a lighting ratio is to meter the individual lights affecting the subject. This is especially important because the formula suggest the combined reading of K+F are the only two light sources ever lighting the subject. On many occasions there are several light sources lighting the subject, and the only way to properly determine the exposure value of each fill light source is to compare it to the key light and only the key light. The correct formula to determine a lighting ratio is K:F. While the correct exposure may be K+F+F+F=Exposure.--107.77.192.197 (talk) 15:03, 3 March 2017 (UTC)

ASC Definition
The American Society of Cinematographers (ASC) defines lighting ratio as (key+fill):fill. The formula is more properly represented mathematically as (key+∑fill):∑fill, where ∑fill is the sum of all fill lights.

The definition has been changed to comport with ASC definition. There should be only ONE definition of lighting ratio. The ASC definition is authoritative. 107.184.247.128 (talk) 22:09, 8 April 2023 (UTC)