Easy to understand graphic explaining the difference between lux and lumens as well as a conversion calculator.
Lux - Unit of Illuminance The number of lux indicates how much light falls on a surface, expressed in lumens per square metre. This light can come from anywhere: a lamp, sunlight coming in through a window, reflections on walls, and so on. To extend our water analogy, illuminance in ...
difference between Lux and Lumens
The light meter has no authority; scene luminance does, and that's what an incidence meter measures. The point is not about the "fictional authority" of the light meter, but rather that exposure for a given scene luminance and ISO does not change regardless of sensor (or film) size. Or ...