ttystikk
Well-Known Member
Yes, and there are threads about them.
Lens and Reflector Optics for COB
- Thread starter robincnn
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wietefras
Well-Known Member
YPF is the PAR measurement corrrected for the McCree RQE chart. That indeed is a much better metric than the usual PPF since it corrects the wavelengths according to how efficiently plants use that wavelength on average. Where PPF counts all wavelengths between 400 an 700Nm at 100%. YPF does the full width of the McCree chart (ie 350 till 750Nm or something) and counts each wavelenght according to value of the McCree curve.
In this case, I think Roger A Shrubber was referring to the belief that reflectors "put the light where you want it".
CobKits
Well-Known Member
no and there is a polar pattern on almost every datasheet
crees look like this:
citizen like this:
which in reality are almost identical, just represented differently
CoB_nUt
Well-Known Member
I have reflectors on the ends of the bars where I keep the tent open solely for that purpose. Heat removal. The other cobs are bare. I want to wrangle in the light escaping out of the tent's open doors.
RandomHero8913
Well-Known Member
So i have a weird question for all of you, is there any camera filter that would be beneficial for us to use at the end of our reflectors? And I guess more importantly would they even work? I ask because I'm tinkering with a Vero18 project and the Angelina reflectors have a 81mm diameter and there are tons of 82mm camera filters for cheap.
I was thinking about using a diffusion lens to try to even out the intensity. If they work maybe test out different filters and the effects. I was just now thinking about using red and blue filters for 4000k lights depending on stage of growth, or playing around with polarizing filters.
Have any of you ever thought of this or know any more about this? Thanks
I was thinking about using a diffusion lens to try to even out the intensity. If they work maybe test out different filters and the effects. I was just now thinking about using red and blue filters for 4000k lights depending on stage of growth, or playing around with polarizing filters.
Have any of you ever thought of this or know any more about this? Thanks
ttystikk
Well-Known Member
Filters do just that; remove light. Therefore not a good idea. Diffusion screens scatter photons. For my money, I want them focused on the target! If you need to cover a larger area, use more chips, as better light distribution is always more efficient. So to summarize; lenses good, filters bad.
Airwalker16
Well-Known Member
You want an even amount of photons across every inch of your canopy If possible.
Randomblame
Well-Known Member
In short, because of light stress which is also known as bleaching.
Mostly a hot spot is created in the middle and you recognize it as unexpected whitening on the leaves or buds! It often looks like a N or Mg deficit.
At first, the leaves become lighter, then almost yellow, and at last they continue to bleach and dry.
Flowers are sometimes just get white tips.
Mostly a hot spot is created in the middle and you recognize it as unexpected whitening on the leaves or buds! It often looks like a N or Mg deficit.
At first, the leaves become lighter, then almost yellow, and at last they continue to bleach and dry.
Flowers are sometimes just get white tips.
Thanx for your answer!
will all leaves get yellow or just those under spot light?
And what about if my COBs photones will be not so much to cause bleaching even in case of hot spots?
I' ve an hotspot with my five 1212 mount as a 50cm "cross" without reflector and so hotspot at least in the central portion and didn' t notice anything light that.
Regards!!!
Randomblame
Well-Known Member
Well, you need probably >1000μmol/s(without add. CO²} to cause bleaching. With CO² up-to 1500μMol/s are possible.
As long as your peak values are below, you will probably not have any problems. But hang it 8" over the canopy and you'll probably see signs of light stress within a week, so it's also important how high your hotspot is.
KonopCh
Well-Known Member
@Randomblame slighty offtopic...
Okay, if you get bleaching then you must dim lights or move it higher.
But... what about "light saturation" when plants are droppy before lights go out? Or when they're stressed (leaf tips turning up)? <--- are these two the same from too much light? Or it the second one because of heat?
Okay, if you get bleaching then you must dim lights or move it higher.
But... what about "light saturation" when plants are droppy before lights go out? Or when they're stressed (leaf tips turning up)? <--- are these two the same from too much light? Or it the second one because of heat?
Randomblame
Well-Known Member
I would say, it can be caused by both too much heat and too much light but also by too low humidy. But if it is too much light, additional yellow discoloration will come later. In any case, it helps if you hang the lamp higher.
Ultra low humidy <25% can also cause droopy lookin plants. Ultrasonic nebulizer could be useful here. I often measured very low RH values near COB's when I placed the sensor in the near to the COB's(8" below). I would check that first...!
Ultra low humidy <25% can also cause droopy lookin plants. Ultrasonic nebulizer could be useful here. I often measured very low RH values near COB's when I placed the sensor in the near to the COB's(8" below). I would check that first...!
KonopCh
Well-Known Member
Hmmm...
I really think I have too strong light. 140W at COBs in 80x80cm tent, 45cm from canopy. Pretty much high I guess, but anyway too much. Temp is 23-27°C, humidity 50-60%. They're starting flower now, but leaf tips are turning up. I don't think it's heat or humidity, because they're in sweet spot. I also don't think 140W is many in 80x80cm tent...
Has anyone compare same light, but one higher (let's say 60+ cm) and one in "sweet spot" (30-40cm)? I really want to see if they yield the same...
I really think I have too strong light. 140W at COBs in 80x80cm tent, 45cm from canopy. Pretty much high I guess, but anyway too much. Temp is 23-27°C, humidity 50-60%. They're starting flower now, but leaf tips are turning up. I don't think it's heat or humidity, because they're in sweet spot. I also don't think 140W is many in 80x80cm tent...
Has anyone compare same light, but one higher (let's say 60+ cm) and one in "sweet spot" (30-40cm)? I really want to see if they yield the same...
Randomblame
Well-Known Member
Okay,
can I ask how much water do the girls consume? Could be also caused by not enough water.
Rinse the pots once to moisten the entire soil could help then maybe.
Water consumption should be no less than with HPS mostly because they need the same or more amount of nutes. If they drink not enough they get probably not enough nutes.
I can remember that at the beginning I made this mistake because I mistakenly thought I needed less water with LED. But this is not the case!
can I ask how much water do the girls consume? Could be also caused by not enough water.
Rinse the pots once to moisten the entire soil could help then maybe.
Water consumption should be no less than with HPS mostly because they need the same or more amount of nutes. If they drink not enough they get probably not enough nutes.
I can remember that at the beginning I made this mistake because I mistakenly thought I needed less water with LED. But this is not the case!
KonopCh
Well-Known Member
@Randomblame they're in autopots (bottom fed). I doubt it's because of pots or heat/humidity. Leaves are little upwards and when is approaching "lights out" they're droppy. DLI too high? I doubt! But this is strange as they're taking whole 80x80cm space (I SCROG 2 plants). They're healthy and nice.
Do you have maybe any data for previous question about distance to plants? I am not active on this forum too much, I only follow this LED section here. I would really want to see the same clone, both let's say under 200W light, but one at 30cm distance, other at 60+cm. Other factors the same.
Do you have maybe any data for previous question about distance to plants? I am not active on this forum too much, I only follow this LED section here. I would really want to see the same clone, both let's say under 200W light, but one at 30cm distance, other at 60+cm. Other factors the same.
OLD MOTHER SATIVA
Well-Known Member
i have successfully run cree 3590's @50 w each with no lens /reflectors.close as 6" away with air movement
no problems
thats on a 4ft plant
ymmv
no problems
thats on a 4ft plant
ymmv
KonopCh
Well-Known Member
At what age?
Randomblame
Well-Known Member
No comparision threads as far as I know. Also it's hard to say what going on without pics.
But if too much light or too high DLI you would eventually see yellow to white discoloration.
I would try to hang the lights a bit higher, the difference in yield is not that high but you get better coverage.
Is there a fan blowing air to the plants? Maybe it's not enough airflow and therefor transpiration is too low.
I'm just trying to find a cause, but right now it's more guessing than anything else.
KonopCh
Well-Known Member
@Randomblame here you go...
First two pics are 3 hours after lights on and the second two pics are 3 hours before lights go out. So after 3 hours and after 17 hours of light...
First two pics are 3 hours after lights on and the second two pics are 3 hours before lights go out. So after 3 hours and after 17 hours of light...