Randomblame
Well-Known Member
Hey, bro! Most of the cheap lux meters are unfortunately not accurate enough without calibration. They can be used to adjust height, uniformity and intensity level of the light but calculated μMol/s numbers will not be accurate in the most cases.@Randomblame I have this in my shopping cart.It's supposed to be a newer model.
Whaddaya think of it?
https://www.amazon.com/Dr-meter-LX1010B-Digital-Illuminance-Luxmeter/dp/B004K0A7I6/ref=dp_ob_title_hi
I've a cheap ebay lux meter that looks almost the same (the red one, wired sensor too, 12 bucks, e3ay) but when I compare the calculated numbers with PAR meter measurings its ~12% too low.
3k/F-stips have a divider of ~69 so 69000lx should be 1000μMol/s/m², right?!
I've used a good PAR meter(a friend has one) and have placed it 10" below the light and have set the intensity level to 1000μMol/s but as I've checked the lux meter readings at the same spot I got only 60.500lx. ~12% less...
IMO it's necessary to calibrate them against an accurate PAR meter or at least to compare them to know how much % it differs. FrankCannon has tested his 8 HL boards with a lux meter last week and compared readings to the μMol/s and lux numbers of a spectrometer and the lux meter was almost 18% too low.
Finally lux meters are still useful but without calibration we could also use a free lux meter app to figure out how to get the best even distribution.