TriplettLT80 LED Illuminance/Light Meter up to 400,000 Lux / 40,000 Fc

Works as advertised and much more accurate than any app.

The media could not be loaded.  Weird problem: when I turn it off, it turns itself on again a few seconds later (see video). Maybe there’s some sort of “auto sleep” function that will save the batteries. Maybe not, maybe I really should just pop them out when I’m not using it.I got this cheap as a “used, like new”’ item and I only plan to use it for hobby projects where I don’t need a pro-grade tool, so this issue doesn’t bother me. But if I had paid full price, this would probably trigger a return.

Using this to measure the bulb quality of a projector. Needed over 300klux and the common, basic ones maxed out at 200klux.

I purchased two light meters: TRIPPLETT LT80 and UNI-T UT383. The UT383 consistently reads 35% higher than the LT80, at all light levels -- indoors (5000K LED lighting), outdoor cloudy, or in full sun. Under an LED grow light (Advanced LEDLights Diamond Series 2014 (very purplish)) the UNI-T reads 400% higher than the Tripplett at any distance! When both meters are placed in direct sunlight filtered thru yellow sheer curtains, they read almost exactly the same. The Relative Sensitivity chart provided with the LT80 leads me to believe it is more geared toward human needs rather than plants, while the UT383 has no reference and may accidentally track closer to the photosynthesis spectrum. This is pure speculation of course, but it is curious that both meters read the same thru yellow curtains. I wonder how the Tripplett would respond if its internal filter could be removed, and I wonder about the LT75 which doesn't claim to have a filter. All in all, the Tripplett seems to be a better meter. I like the averaging function and the extra digit for low lighting (but it's rather moot because light levels are not that precise anyway). I like the Tripplett, but the filter may not be best for plant grow lights. Great for comparative reference, tho; hard to judge whether my plants are getting enuf light just by eye. I just have to remember that LED growlights may be providing beneficial photosynthesis wavelengths outside of the spectrum that the LT80 is measuring.