Lens and Reflector Optics for COB

What Optics do you use in your DIY Lamp

  • No Optics

    Votes: 132 45.4%

  • Glass Lens

    Votes: 58 19.9%

  • Reflector

    Votes: 118 40.5%

  • Silicone Lens

    Votes: 23 7.9%

  • Other

    Votes: 6 2.1%
  • Total voters
    291
rocho said:
Hi! I can't find available any vero29 gen7 rrflector holder.

Could you help me to find some cree ideal holder that can be adapted as substitute of c13584?

Maybe c14036? 502100? 502300? Which above these, if any?
Thankyou very much and have a good day!
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I was under the impression that the old vero holders fit the new ones?
 
Lens/reflector for gen 7 Vero 29?
Kingbrite have 60/90/120 lenses... Do you recommend 90? What's loses and gains? Any read here for sunday morning?
Btw, why 120 lenses if COB already have 120 view angle?
 
Just from my experience i like my cobs without lens. They seem brighter and i dont really need lens or reflectors since my room is all white. I keep my lights about 12 to 14 inches away from my tops and i easily pull 1.5 gpw. I built 4 separate lights (all with 18 cobs of 3070) and i pull at least 3 lbs of dry and cured bud off each light.
 
How is the light distributed from most COBs? Is it even across the 120 degrees? I've been trying to figure out how to DIY my own COB set up and I'm running into this stumbling block as to where to place them and if I should bother with reflectors/lenses in a closed room.
 
Forrestfirebuds said:
Just from my experience i like my cobs without lens. They seem brighter and i dont really need lens or reflectors since my room is all white. I keep my lights about 12 to 14 inches away from my tops and i easily pull 1.5 gpw. I built 4 separate lights (all with 18 cobs of 3070) and i pull at least 3 lbs of dry and cured bud off each light.
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Yea... what about penetration and unwanted popcorn buds?
 
KonopCh said:
Yea... what about penetration and unwanted popcorn buds?
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I get a solid 30 inches of light penatration for sure. And yes my bottom buds are smaller than my tops but they are still solis buds. I hate messing with the lil popcorn buds so ive done pretty good at dialing in my canopy with all the grow techniques like lolly popping, super cropping, and some deleafing. Seriously i love the cobs and their penatration and even light coverage. I really dont have hot spots at all besides directly under the cobs but i still dont consider it hot spots like with hps.
 
HideousPenguinBoy said:
How is the light distributed from most COBs? Is it even across the 120 degrees? I've been trying to figure out how to DIY my own COB set up and I'm running into this stumbling block as to where to place them and if I should bother with reflectors/lenses in a closed room.
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I have my 3070 cobs spread about 14 inches apart from each other with no lens and i have awesome light distribution. Like i told the other guy i dont have hot spots really besides being directly under the cob. I could just imagine how they would perform if my cobs were 3590 instead of the 3070. I would think you would have to raise the light so you dont get light burn because i noticed my plants getting light burn when they were atound 10 inches from them. I get good light penatration too.
 
Reflectors catch about 20% of the light from the COBs. The rest is already within the 90 degree angle. On the other hand, COBs with reflectors lose about 10% of the total light (even more when used for a while). So they actually lose about half of the light that they are supposed to send down to the plants. You are much better off just letting that light find it's way to the plants on it's own.

You will actually see more penetration from shallow angled light than from light that goes straight down. If you have a filled grow, look at your canopy from straight above. Pretty much a closed green field. Now look under a shallow angle and you can see right between the leaves.

Malocan showed he had 20% less light with reflectors over his grow area. This is because you don't just lose light on the reflectors, you also need to increase the height of the fixture to still get a uniform light distribution. That means more wall losses and therefore more light lost due to using reflectors.

@HideousPenguinBoy, You really don't need to know the distribution pattern of a COB (it's in the datasheets though). All you have to do is to distribute the COBs as evenly as possible over the grow area.

When you finish your light you can get the uniformity you want by adjusting the height of the fixture over the plants. When you go too close you get hotspots. Just keep increasing the height until you see a uniform light. I use around 12", but it depends on the light intensity per COB (many small ones will need to go lower and a few big ones would need to be higher up).
 
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I run 80 degree lenses on my CXB3590 chips, run at 56W each. I get excellent footprint without a lot of excess light scattering, ideal for arrays. I'm currently running each 225W module over a 2x3' footprint, for 37.5W/sq ft. Since that's an awful lot of light, I'm contemplating going down to 2'x4', for just over 28W/sq ft. The lenses should still help the lights pack plenty of performance into that footprint.
 
The thing is, you pack less performance in the same footprint when you use opticals. You lose light.

The mistake people make is to test one COB with a lens/reflector and measure the light in the middle straight under the COB. Yes then of course you will measure a higher PPFD, because the light is more bundled to the center. Trouble is, you lose more light somewhere else. About 10% to 15% depending on how long you have been using the reflectors (they lose reflectiveness real quick). Plus extra wall losses because you need the extra distance to the canopy when using opticals.

I guess it's hard to understand because a simple (incorrect) measurement seems to indicate the opposite, but if you think about it it should be possible to follow the actual physics.

Besides that, Malocan measured the average light over the whole grow area. With and without reflectors. It was on average 20% less light when the reflectors were on. So it's not just theoretical, it's been tested.
 
sometimes its not about the raw amount of light produced, but how well you can place it. theres a saturation point and once you reach it, anything else is just rapidly diminishing returns. if you can use just the amount of light you need, focused where you want it, isn't that the actual measure of efficiency?
 
I run lenses with all my discreet leds (they came like that) and run my COBs with lenses much more with than without but both work well. I run perpetual with individual LSTed plants and at times so my light needs aren't always the same.

I have a Photon 180 with the 120* lenses that even bare has cob holders that recess the cob a little in a white cone shaped mount that already shapes the light a bit. Those big lenses make for an extremely even coverage. I prefer to be agnostic bout this so I can be happy either way. The area of useful light is shaped differently with a shallower but wider pillow of light from bare COBs and a bit smaller and deeper pillow with lenses.
 
Roger A. Shrubber said:
sometimes its not about the raw amount of light produced, but how well you can place it. theres a saturation point and once you reach it, anything else is just rapidly diminishing returns. if you can use just the amount of light you need, focused where you want it, isn't that the actual measure of efficiency?
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That's not what reflectors do though. They mostly make light distribution worse by bundling the light into more or less hard edged circles. So yeah I agree that it's good to have uniformly distributed light, but the way to achieve that is wide beam angles with some overlap.
 
Roger A. Shrubber said:
sometimes its not about the raw amount of light produced, but how well you can place it. theres a saturation point and once you reach it, anything else is just rapidly diminishing returns. if you can use just the amount of light you need, focused where you want it, isn't that the actual measure of efficiency?
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it is referred to as YPF
 
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