Using lux for measuring light
Anyone familiar with using this and have recommended ranges? I found some results on growweedeasy but I'm curious if anybody on this forum uses this technique. I see ppfd used a lot here but I cannot afford one of those meters currently and I can measure the lux for free with my phone app.
You can add your own money to be able to buy it. By borrowing or exchanging merchandise, it costs you to purchase lux.
Lux meters have a hard time detecting red and blue lighting. https://ledlightinginfo.com/can-a-lux-meter-measure-led-light
They can be great for incandescent bulbs or white light but are often inaccurate for led lights with red and blue colors. The link above explains.
LUX meters work off the principle of the visual response curve of our eyes. Which is hypersensitive in the regions of green and yellow. This means that you can only accurately measure and compare data from the same type of lighting system. This is because when the spectrum changes, the LUX value changes also with respect to the sensitivity curve. Even when the actual quantity of light is the same. Blue and red light will measure lower than green and yellow.
Applying conversions to compensate for the spectrums work fairly good. As long as the conversion value is fairly accurate with respect to your own lights spectrum curve. This is fine for systems such as gas discharge systems where the technology is practically uniform between manufacturers and their products. But with LED there can be a varying level of unique spectrums that can fall outside the conversions equation.
After reading a lot, you can use LUX as a general measurement to get a useable figure. The trick only works on white LEDs.
Take the LUX and multiply by .016. There are other estimates such as .015, but if you have a tape measure, a good light, and feel you can trust the PAR map any good LED maker provides you can check your figures and adjust to come up with the provided PAR figure. This works somewhat well using my Viparspectra Pro 1000, and 1500 for what it is worth. All of that said this is only a S.W.A.G. figure best used for checking drop off at a distance but it is some help. A real PAR meter, that I can't afford either is the right way.