Bonjour,

J'ai trouvé pas mal d'info sur le web :

Tables de conversion Lux <> EV (IL)
Conversion Chart
ou
Conversion Tables for LUX to EV and EV Exposure Tables for Infrared Photography. 999WED.com.

Et il semble y avoir tout sur wikipedia en anglais : Exposure value - Wikipedia, the free encyclopedia

Notamment la formule de conversion Lux <> EV : L = 2^(EV - 3)
"
For a given ISO speed and meter calibration constant, there is a direct relationship between exposure value and luminance (or illuminance). Strictly, EV is not a measure of luminance or illuminance; rather, an EV corresponds to a luminance (or illuminance) for which a camera with a given ISO speed would use the indicated EV to obtain the nominally correct exposure. Nonetheless, it is common practice among photographic equipment manufacturers to express luminance in EV for ISO 100 speed, as when specifying metering range (Ray 2000, 318) or autofocus sensitivity. And the practice is long established; Ray (2002), 592) cites Ulffers (1968) as an early example. Properly, the meter calibration constant as well as the ISO speed should be stated, but this seldom is done.

Values for the reflected-light calibration constant K vary slightly among manufacturers; a common choice is 12.5 (Canon, Nikon, and Sekonic[5]). Using K = 12.5, the relationship between EV at ISO 100 and luminance L is then : L = 2^(EV - 3)"