enfun fs-2000 valeur en luxmètre

lux varies due to how it measures light and the slight variance in grow light characteristics - like CCT differences. Any sort of variance in RBG ratios will result in different lux values for the same intensity of light. So, it can still be a useful tool. It just relates to your light and maybe not so much other lights. Also, a phone app lux meter will read 2x higher than a 10 dollar handheld lux meter device. the camera measures from a much larger angle than the little devices with the white bulb thing over the probe. Might be 20k or 50k, lol. BUT, you can't just target a klux or umol/s of PAR and assume it will be okay. There is a need for trial and error. The growth pattern is your guide. Too lanky requires more. Too tight requires less. Simple as that. Once you find a power level that results in ideal growth, take a measurement and you can mostly skip this process next time. Changes in temperature and humidity will impact max light you can give per day, too, so you may find seasonal variations that require new measurements. Take notes. Read up on Daily Light Integral (DLI) - the wiki is fine. This will give a proper understanding on how to measure and perceive light. This stuff is proportional to hours of operation. So, if you deduce a good value for 18h, you'll need 150% of that value over 12 hours. (18/12 = 150%). this assumes you keep same hanging distance to cover same area.