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Lumens or PAR, more is still more.
Because most LED fixtures use lenses to concentrate and direct the light from the chips, they do NOT follow the inverse square law of light attenuation, rather their graphed curve of light reduction looks a lot like the inverse square law- only counting from a foot or two behind the fixture.
This design feature of LED lighting makes them much less usable in close quarters, and makes them a very poor candidate light source for movers since the light is so sharply directed.
Finally, if you haven't seen anyone hanging hps lights vertically down by their plants on this website, it's only because you haven't looked very hard! You ever heard of a 'tree grow', buddy? LOL
Not exactly... lumens are a weighted measurement...if the 2 lights had identical spectrums it could be comparable but that is the beauty of LED, more par...less wasted light in the lumen(yellow, green) area so they aren't quite equal. A light that has more lumens but less par is not more to the plants. Even same par in different spectrums could be more or less to the plants. But my point is that par is the unweighted measurement of the light within 400nm-700nm which is what light range drives photosynthesis. Then within that range certain wavelengths are more efficiently used by the plants. I'm know you know all this, I am just defending why I chose what I chose.
I didn't know about the lens changing the source location in the inverse square law. That might clear up some measurements vs math things I have been seeing. I just read up a little on the modified inverse equation. I would like to know the exact way to measure and use the law based on lens angles and what not.
I know about vertical bare bulbs...not the same as a sideways hood or led unit. With vertical bulb you use the whole area around the bulb...I've seen your thread and plenty others. And your are comparing your method vs mine...which are different and thus have different requirements.
Let me ask you this...If you could change nothing other than the lights in my situation(starting 12/12 with (22) 18"-20" plants in 5g's in 4x10) how would you do it...remember I'm only using 1099w-1256w. I used to use (3) 600w but many would use (3) 1000w. But I am comparing to 600w not 1000w.
My point was to show these what these led's could do in a larger scale situation. Not 1 light in a closet.
I think that my way is the most practical way to use my lights and the space I have. Apaches are 1000$.
Plus I will eventually fill the other side and need the rest of my lights. And I do think a light mover would increase coverage successfully, you just can't move them as far. I've seen them used very well.