THIS APP IS NOT A LIGHT METER AND DOES NOT MEASURE LIGHT
Key Light Exposure Calculator is a tool for filmmakers useful in determining how much incident light is necessary to make effective exposures at various combinations of Frame Rate, T stop (Aperture), ISO (Sensitivity), and Exposure Time (Shutter Speed / Shutter Angle).
Key Light determines its results using established photographic formulae to find the appropriate exposure parameters. Resulting Incident Key Light is the amount of light required to correctly expose for an 18% Reflectance Gray Card.
Designed with High Frame Rate Videography in mind, use Key Light to help you determine how much light is required to make correct exposures at very high frame rates and short exposure times. Also useful for low light and high ISO photography in determining if available light will be sufficient.