Lenses and Reflectors

Most LED lights on the market use lenses, and a lot of the sellers spend a lot of time talking up their particular lenses. As I've learned more about LEDs, it's become clear that there are 2 different kinds of lenses: Primary and Secondary.

For LED grow lights, it's my understanding (as detailed below) that the best lights will use primary lenses, ideally will not use secondary lenses, and that using reflectors isn't as efficient as using secondary lenses (this applies only to LEDs– not other grow light technologies). Companies that use primary lenses only were put in the "Good" category above; companies that use secondary lenses or reflectors were put in the "Questionable" category, and companies that don't use primary lenses or lied about what their secondary lenses or reflectors do were put in the "Bad" category.

You can see all of the lens and reflector data for each model light in the table at the bottom of this page.

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Primary Lenses

Primary lenses are placed directly on the light-emitting portion of the LED, because they increase the efficiency of getting light out of the silicon. Even though lenses always lose some light, the extra light primary lenses harvest from the silicon is more than this loss. So basically, if you don't have a primary lens, more of the light you're paying to create is just trapped bouncing around inside the LED and never gets to your plants.

Almost all LED grow lights use primary lenses for this reason– it is just more efficient, and it costs almost nothing to add a primary lens. There are a couple notable exceptions: both Area 51's models and Hydro Grow's Sol lights don't use primary lenses, and I can only guess at the reason why. It can't be just because these are both "COB" LEDs, as there are other COB LEDs with primary lenses, though they all seem to be a much lower-wattage COB. My guess is that these higher-power COBs are already running so close to a damaging overheating threshold that the addition of even a little plastic would overheat them, but I'm just guessing based on what I've read here. Whatever the reason, buying an LED grow light without primary lenses seems like a bad idea.

Secondary Lenses

Secondary lenses are placed beneath the primary lens to focus the light into a wider, or more frequently, narrower beam. It is important to understand that secondary lenses (sometimes called "optics" in marketing material) do NOT increase the amount of light, they just change how it spreads out. In fact, secondary lenses decrease the total amount of light that gets to your plants because some of the light is reflected off the lens and some is absorbed by the lens. The amount of light lost depends on the exact lens, but 8%-15% loss is pretty standard.

There are reasons you may want secondary lenses for lower-powered LEDs; they focus the light to make it more intense. But just like adjustable-beam flashlights, when you focus the light into a tight beam to make it more intense, the total coverage area drops. A seller can increase some PAR measurements with secondary lenses too, but this isn't necessarily a good thing– see my dissection of a PAR deception for a full rundown.

It seems to me that you only really need secondary lenses if the light isn't intense enough in the first place. Indeed almost all of the lights I compare that use secondary lenses are using 1W or 3W LEDs, or a mix of 3W and 5W LEDs– though I can't tell if the 5W chips also have secondary lenses or not, or even if the 5W LEDs are being run at anything close to their full potential.

From my personal experience, I can say that an all-3W LED panel without secondary lenses didn't penetrate plant canopies very well but had a decent growing footprint–perfect for a sea-of-green (SOG) or screen-of-green (SCROG) type grow. An all-3W LED panel with secondary lenses did penetrate the canopy much better and worked better with taller plants, but it had a much smaller footprint.

Basically, I'm not a fan of secondary lenses because of the reduced footprint, reduced efficiency, my feeling that they are most often added for deceptive purposes, and because they just aren't necessary if your LED grow light is bright enough to begin with.

Some companies are lying about what their secondary lenses can do and that's just wrong.

Reflectors

Traditional incandescent, fluorescent, induction, plasma and HID light bulbs put out light in all directions (360 degrees around the bulb), so they need reflectors to bounce half of their light back down to your plants. LEDs only put out light in 180 degrees or less, so they don't need reflectors because they aren't aiming light at the ceiling to begin with.

Since the efficiency of LEDs is increased by putting a primary lens on the chip, as discussed above, the lens can be used to focus the light more down toward your plants so it isn't illuminating the walls out to the sides, and there is no need for a reflector to do that task.

Just like lenses, reflectors aren't perfect at redirecting light, and they cause about 10%-20% of the light to be lost. However, reflectors degrade over time as they oxidize and lose efficiency; this is why some HID hood manufacturers and experienced HID growers recommend getting new reflectors every year. Since LEDs can use lenses that don't degrade in this way and get more light out of the LED to begin with, it never makes sense to use a reflector with an LED grow light. I would not recommend purchasing any LED light that incorporates a reflector, as it means the designer didn't understand how to make the most efficient long-term use of LEDs.

The models mentioned above that don't use primary lenses do use reflectors to try and salvage some of the misdirected light. So, they start out wasting light by not using a primary lens, and over time as the reflectors degrade they waste even more. A lose-lose situation.

Kessil is the only company compared here that uses both reflectors and primary lenses, and this makes no sense to me. If they wanted to change the way their light spreads, they would be better off adjusting the angle of their primary lens so they don't waste light in the reflector. If they wanted a really narrow beam angle, they would be better off using secondary lenses than a reflector.

Note: I'm only talking about reflective surfaces on the light itself; it usually makes sense to surround your grow with reflective walls to salvage as much light as possible and get it back to your plants. Flat white surfaces (such as flat white paint) work best for this, and white in general (even glossy) works better than mylar or mirrors–it actually reflects more light.

The Bad: Magnified Lies

Some LED sellers are just blatantly lying about the function of their secondary lenses or reflectors. For secondary lenses they claim an increase total power output without additional electricity, or that they increase light intensity while maintaining the same or larger coverage area. The only way to make light from an LED more intense is to focus it into a narrower beam, decreasing the coverage area. You can pull the light up higher to make it cover a larger area, but the inverse square law of light dictates that increasing the coverage decreases the intensity.

If it were really possible to increase the total power output of the light without using more energy, or to maintain the same intensity (power) over a larger footprint and violate the inverse square law of light, these companies would be stupid to focus on the LED grow light industry– they could quickly become billionaires in the energy industry instead. If these claims were possible, you could harvest energy for free by putting a solar panel underneath and sending the power back in to multiply under the lights, creating a perpetual motion machine. Your house, your car, even the grow lights themselves could just be powered by one of these magic energy-multiplying LED lights–just plug it in to get started and then you'd never need to pay the power company again!

So these claims are just blatant lies, and I wouldn't recommend purchasing any of these lights:

  • Hydro Grow describes their X-Pro series: Our secondary lens technology collects and refocuses the light that the primary lenses missed and re-emits it to your plant canopy. The X2 lens has a 25% increase in performance, compared to the previous X1 lens, making it 5.7x as intense as the market standard 90 degree lense. Even better, our optics grade secondary lenses eliminates the use of glass on each unit, preventing potential shattered glass while at the same time creating a larger coverage area. You just can't increase the intensity and create a larger coverage area at the same time. Additionally, any light the primary lenses "missed" is lost forever inside the silicon of the LED.
  • Lush Lighting sells models that are identical in every way except one has a secondary lens, and one does not:
    Primary Lens ModelPrimary + Secondary Lens Model
    NameAdvertised FootprintNameAdvertised Footprint
    Dominator4'x4'Dominator 2X4'x4'
    Dominator XL5'x5'Dominator 2X XL5'x5'
    Luminator3'x3'Luminator 2X3'x3'
    Vegitator4'x4'Vegitator 2X5'x5'
    Herbalvador4'x4'Herbalvador 2X4'x4'
    The advertised footprints sizes for the lensed ("2X") and un-lensed models are exactly the same, except the lensed Vegetator 2X model has a 5'x5' footprint, whereas the un-lensed Vegetator has a 4'x4' footprint–they actually claim the lenses making their light beams narrower are increasing the footprint size! They even have fancy diagrams showing the lensed models having more intensity over the same footprint as the un-lensed models. These diagrams also misrepresent how the light spreads; you can't get a square footprint out of their rectangular light–2 lies in 1 picture!
  • Spectrum King claims that their lights' reflectors make 100% of original LED lumens go directly to your canopy. No reflector is 100% efficient! Bright Light LED (the parent company of Spectrum King) tells the truth about their reflectors on their website page for the exact same light fixture, saying that the reflective rate could reach up to 92%, but they lie about this on the Spectrum King website. The Spectrum King page also states that for HPS bulbs light reflects in hood so only 50% of original lumens make it to your canopy which is also a lie; hoods are designed with reflective surfaces, and while they aren't perfect, a lot more than 50% of the bulb's light output makes it to your plants. This isn't the only time they exaggerate their lights' features and exaggerate HPS bulbs' failures; it sure seems like they are trying to compensate for their lights being inadequate.

Lens and Reflector Data for All Lights

The data table is very large- you may need to scroll side-to-side as well as up and down to see the whole thing. Larger screens help! If you're only looking for one company or light model, enter the name in the search to only show those results.

CompanyConclusion RankingProductLight TypeSecondary LensesReflector
Diamond Series DS 100 - Extreme 3w
Yes
Diamond Series DS 200 - Extreme 3w
Yes
Diamond Series DS 300 - Extreme 3w
Yes
Diamond Series DS 400 - Extreme 3w
Yes
Diamond Series DS 600 - Extreme 3w
Yes
Diamond Series DS 800 - Extreme 3w
Yes
XTE Series DS XTE 100 - 5W LEDs
Yes
XTE Series DS XTE 200 - 5W LEDs
Yes
XTE Series DS XTE 300 - 5W LEDs
Yes
XTE Series DS XTE 400 - 5W LEDs
Yes
Diamond Series EX-Veg DS200
Yes
Diamond Series EX-Veg DS300
Yes
Diamond Series XML DS XML 150
Yes
Diamond Series XML DS XML 350
Yes
Diamond Series XML DS XML 650
Yes
AT-120WB (White and Blue LEDs)
Yes
AT120RB (Red and Blue LEDs)
Yes
AT120W (All white LEDs)
Yes
AT120WR (White and Red LEDs)
Yes
AT-600-WR2 (White and Red)
Yes
GL100LED Full Spectrum 300W LED
No
GL80x5LED Full Spectrum 400W LED
No
Full Spectrum 600 Watt LED
No
GL140x5LED Full Spectrum 700W LED
No
Full Spectrum 900 Watt LED
No
Full Spectrum 1200 Watt LED
No
GL25LED Full Spectrum 75W LED
No
GL25LED Full Spectrum 135W LED
No
GL25LED Full Spectrum 180W LED
No
W90-3000K
No (no primary either)
Yes
W90-4000K
No (no primary either)
Yes
W90-5000K
No (no primary either)
Yes
PhytoMAX 200
No
PhytoMAX 400
No
PhytoMAX 600
No
PhytoMAX 800
No
PhytoMAX 1000
No
SPYDR 600 START-MAX Spectrum
No
Yes
SPYDR 600 GROW-MAX Spectrum
No
Yes
SPYDR 1000 GROW-MAX Spectrum
No
Yes
SPYDR 1200 GROW-MAX Spectrum
No
Yes
Solar Storm 880W
No
Solar Storm 440W
No
Solar Flare 220W LED VegMaster
No
Solar Flare 220W LED BloomBooster
No
Solar Flare 220W LED FullCycle
No
Solar Flare 110W LED VegMaster
No
Solar Flare 110W LED BloomBooster
No
90 Watt LED All RED G8 Flowering BOOST
No
240 Watt Full Spectrum G8LED BLOOM only
No
450 Watt Full Spectrum G8LED BLOOM only
No
240 Watt Full Spectrum G8LED Grow Light
No
450 Watt Full Spectrum G8LED Grow Light
No
600 Watt Full Spectrum G8LED Grow Light
No
900 Watt Full Spectrum G8LED Grow Light
No
E60
Yes
RX30
No
L4A Series 10 (refurbished)
No
LX601 C-plate
Yes
LX601 G-plate
Yes
LX602
Yes
21X-PRO 36W
Yes
84X-PRO 120W
Yes
126X-PRO 200W
Yes
168X-PRO 270W
Yes
189X-PRO 290W
Yes
336X-PRO 500W
Yes
420X-PRO 600W
Yes
Sol 1 (45 Watt Configuration)
No (no primary either)
Yes
Sol 1 (85 Watt Configuration)
No (no primary either)
Yes
Sol 2 (45 Watt Configuration)
No (no primary either)
Yes
Sol 2 (85 Watt Configuration)
No (no primary either)
Yes
Sol 4 (45 Watt Configuration)
No (no primary either)
Yes
Sol 4 (85 Watt Configuration)
No (no primary either)
Yes
Sol 6 (45 Watt Configuration)
No (no primary either)
Yes
Sol 6 (85 Watt Configuration)
No (no primary either)
Yes
Sol 9 (45 Watt Configuration)
No (no primary either)
Yes
Sol 9 (85 Watt Configuration)
No (no primary either)
Yes
NeoSol DS
No
NeoSol NS
No
NeoSol LS
No
H380
No
Yes
H350 (Magenta or Purple models)
No
Yes
H150 (Magenta or Purple models)
No
Yes
H150 Blue
No
Yes
H150 Red
No
Yes
K3 - L300
Yes
K3 - L450
Yes
K3 - L600
Yes
K3 VEG L600
Yes
K5 - XL750
Yes
K5 - XL1000
Yes
90 watt LED Grow Light UV
?
90 watt LED Grow Light HO (Vegetative Model)
?
BlackStar 480 watt LED Grow Light HO V2.0
?
BlackStar 480 watt LED Grow Light UV V2.0
?
BlackStar 180 watt LED Grow Light HO V2.0
?
BlackStar 180 watt LED Grow Light UV V2.0
?
BlackStar 240 watt LED Grow Light HO V2.0
?
BlackStar 240 watt LED Grow Light UV V2.0
?
Lighthouse Hydro ION 8 426w FSF LED Grow Light with UVB
?
Lighthouse Hydro ION 8 1546w FSF LED Grow Light with UVB
?
BlackStar Chrome 180w LED Grow Light FSF
Yes
BlackStar Chrome 270w LED Grow Light FSF
Yes
BlackStar Chrome 405w LED Grow Light FSF
Yes
BlackStar Chrome 720w LED Grow Light FSF
Yes
BlackStar 600 watt LED Grow Light UV
?
BlackStar 900 watt Commercial Grade LED Grow Light UV
?
LumiGrow Pro 650
No
LumiGrow Pro 325
No
DOMINATOR
No
DOMINATOR XL
No
DOMINATOR 2X
Yes
DOMINATOR 2X XL
Yes
Luminator
No
Luminator 2X
Yes
Vegetator
No
Vegetator 2X
Yes
Herbalvador
No
Herbalvador 2X
Yes
Mars II 400w LED Grow Light
No
Mars II 700w LED Grow Light
No
Mars II 900w LED Grow Light
No
Mars II 1200w LED Grow Light
No
Mars II 1600w LED Grow Light
No
Reflector-48
No
Yes
Reflector-96
No
Yes
Reflector-144
No
Yes
Reflector-192
No
Yes
MarsPro 160LED Epistar-160
No
Yes
MarsPro 320LED Epistar-320
No
Yes
MarsPro Cree-128
No
Yes
MarsPro Cree-256
No
Yes
P150
Yes
P300
Yes
P450
Yes
P600
Yes
P900
Yes
P1200
Yes
P4-XML2
Yes
P9-XML2
Yes
MAX-600
No
MAX-1200
No
Illuminator 100W
No
Illuminator Jumbo 200W
No
Illuminator Commercial 400W
No
Mother Keeper 100W
No
300 Series 90° reflector
No (no primary either)
Yes
300 Series 120° reflector
No (no primary either)
Yes
400 Series 60° reflector
No (no primary either)
Yes
400 Series 90° reflector
No (no primary either)
Yes
400 Series 120° reflector
No (no primary either)
Yes
400+ Series 60° reflector
No (no primary either)
Yes
400+ Series 90° reflector
No (no primary either)
Yes
400+ Series 120° reflector
No (no primary either)
Yes
M6
Yes
M9
Yes
M16
Yes

Comments

2 thoughts on “Lenses and Reflectors”

  1. ive got blue led’s to increase my plants vegetative state, where would i buy a primary lense to build them into a light panel

    1. Hello,
      The primary lens is part of the packaging of the LED itself; I believe it has to be bonded to the LED die to work efficiently, so it isn’t something you can add later. You can get secondary lenses for LEDs but which one you need depends on exactly which LEDs you have. Your best bet is to check the LED manufacturer’s website.

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