Hi, Shane here. Thanks for watching, Please hit the like button and subscribe here: www.youtube.com/@MIGROLIGHT?sub_confirmation=1 Buy my Grow Lights here: migrolight.com/ Follow us on: Instagram:instagram.com/migrolight/ Facebook: facebook.com/MIGROLIGHT/ TikTok: www.tiktok.com/@migrolight
Also Dr Bruce Bugbee is another man who you should look into and trust when it comes to grow lights and plants/photosynthesis etc especially if you want a more in depth look into certain things. He’s done a lot of work with cannabis Lately too. Migro is the man when it comes to grow light comparisons etc tho, That’s for sure.
Well you should learn the difference between laws and theories. If in fact anyone proves the law does not apply to specific light sources they would be in science journals for disproving a law. It would only be a theory if any lights were found that did not adhere to the law. He is misrepresenting facts as he misinterprets his readings.
@@swskitso actually, you are still using those words improperly from a scientific standpoint. In Science, a Law (like the Law of Gravity or Newton’s Law of Thermodynamics) explains/predicts how objects (including things like light particles/photons) will behave within given conditions. It takes overwhelming amounts of objective data for something to become a Law in Science. A Theory in Science is an explanation for how or why something occurs the way it does. For instance, the Theory of Gravity is our best current understanding of how Gravity works. In no way does it try to argue whether or not Gravity exists. What Shane is offering here is neither a Theory, nor a Law, but instead a Hypothesis, which is a tentative statement/idea about the natural world which can then be tested and either corroborated or proven false. Unfortunately for him, his experimental design is flawed and so does not show what he originally thought it did and so in no way disproves the Inverted Square Law (and as you said, disproving of an actual Scientific Law would lead to a truly monumental shift in Scientific understanding and our paradigm about the world around us and would put your name all over the Scientific community). ✌️
Finally, Shane's take on inverse square law. So much controversy on this subject. Love how u break it down to "actual" science and laws that we can understand without needing a degree👍 nicely done Migro👏
Actual science would show the inverse square law in effect but by measuring multiple light sources from the LED its an inaccurate measurement and measuring indirect light from the HPS is inaccurate as well. This is terrible science.
@@swskitso You completely missed the point you donut. This isn't setting out to disprove the law, it's setting out to disprove its applicability when discussing grow light heights. Internet experts incorrectly assume that doubling the height of a grow lamp will 1/4 the light output reached to the plants. This is incorrect.
What a great video. While of course the inverse square law holds true as a pure physics/geometry exercise, as you show there are multiple reasons that the inverse square law doesn't hold up in a grow room application. Well done.
If he accounted for the fluence map through geometric parameters we would see inverse square. This would account for gradients and spatial variance of fluence, which is not needed in the case of isotropic radiation from a point source.
Thank you Shane for the work you do for us! The time and energy you sacrificed to perform the experiments and give real data is extremely appreciated here!
One thing that was left out was the effect of the shape of what is receiving the light. A sphere will see much more of a consistent drop off compared to a flat object like a leaf. A leaf close to the center of a light bar is getting very little light from distant diodes, but when you back up a leaf it is then collecting much more from distant diodes. In some cases it can get brighter as you back away.
Obstruction---a topic ive never seen really debated or testet on UA-cam. The smaller your source of light, the more leaves wont get direct light. the perfect panel would cover 90% of the complete surface, only allowing some air to pass by. I think this is even more important than the naked efficiency. It is another form of efficiency. Efficiency on paper can be deceiving. take a cob for example. The light is distributed well if its high enough. At least on paper and on the sensor. But once the canopy grows and is not levelled anymore, many leaves will block other leaves from direct light, because the source is so small.
Thanks again for the great content and info. My whole growing mindset has changed since I started watching your channel. Par meters, I now understand, tell the real story about what my plants are receiving. Now I know if something is wrong in the grow room that it's not the lighting. Happy growing all. Go Shane!
I would to see Shane take his light spectrum meter outside on cloudy days and see how clouds effect the light spectrum. Which colors are lost most in the clouds. I have a lux meter that I convert to PAR. If the clouds are real white and you have to squint is is around 600. As soon as the clouds have any gray to them the par goes from 100 to 50.
To include not deploying the cmh as intended vs the led as engineered. AND… using the same quantum sensor to measure the par. Hid sensors are different than led sensors according to Bruce Bugbee✌️
I just imagined light speed travel with the help of your comment. It'll be possible but not weird or however we've imagined it in scifi etc. And aye im totally serious. Id never thought about theories and facts concerning physics. Im just rambling. Love you, Shane, and Migro 🖖🖖🖖
Everybody’s grow space does not have the same reflective material that you use so when you test your lights you’re in fluctuating the numbers because of your reflective test area when I tested x-ray machines we didn’t test with the scattering
I’m happy to see this video being made. I see people in massive facilities getting light lifters when in reality they have a lit plane so it makes little to no difference how high they put their lights. It’s hard to convince people of that.
Many of us measure with a cell phone app that is different from a genuine par meter because it's lens is more flat and directional than the semicircular lens of the par meter. 120 degree angle measurement with a phone app is important for getting light penetration into the sides of a plant is an important measurement this video ignores causing many people to miscalculate the shape and underestimate the usable size of their lighting footprint. Bruce sells Apogee so he also excuses this measurement which is a valuable tool for decisions.
Shane …. Wondering if you could please do this test …. An old photographer’s trick to calculating light. It’s based on cameras f/ stops which are converted to inches, feet, yards whatever. So there’s f/2, f/2.8, f/4, f5.6, f/8, f/11, f/16, f/22 So for our example f/16 = 16” from light to canopy. When you raise the light to 22” the reading should be 1/2 the amount, theoretically anyway. Would this be an interesting quick test for you to try ?? Thanks for all your content
The inverse square law is just a fact of life. Your measurements are not disproving anything. When you double the distance of the array only the diode directly above the sensor will have 1/4 the photon flux density. All other diodes in the array will not have moved double the distance from the sensor thus will not have 1/4 the pfd.
Scattered par from reflective material is not true primary beam energy is lost from the light photons twhen it’s redirected to the primary source but scatter will raise density numbers but is not the primary beam plus the inverse square law does not have reflection in the diagram and is based on the fact all photons 100% primary beam are in the equation that is I physically impossible to do Inverse square law is just a basic law like gravity but we all hit terminal velocity at different speeds
Inverse square law is more accurate when testing a single light source unlike leds with multiple lights of course inverse square law gets thrown out the window when scatter light photon from reflection are used in the equation that’s why your more closer too the inverse square with out the reflection walls creating noise inverse square is accurate when the testing is more actually done
The inverse square law is not wrong. You are just using an integral of inverse square laws. Just because planes can fly doesn't make gravity theory wrong.
Thats all gravity is, a theory. Never been proven to be a force. Was replaced 107 years ago with Einstein gravity - Not a force. None of these gravity theories have ever been proven to exist. They are just stories that brainwashed people believe in. 😎
Decrease the object image distance OID or move the light down you will i crease the intensity so yea it is correct the theory of the inverse square law it just does not work in real life due too other influences like air resistance to gravity
Thank you.....for ALL YOU DO ! YOU....are the GO-TO SOURCE, AT least for myself, when researching which led to invest in......I recently purchased the Grow Light Science 300 , to replace my CMH , in my vegetation sector...which I am hesitant, as I propagate/pre-veg under the Growers Choice ROI-200...which as a Full-spectrum w far red , CREATING MASSIVE BRANCHING.....the CMH is a more blue leaning spectrum which grows strength and stretch..... which sets me up for an AWESOME bloom cycle under an HLG-600R and the PHOTONTEK-600PRO......The results are AMAZING.... Thanks again , sooo much for ALL you do as you have been an extremely valuable ASSET to me....Thank you !
@@simonaek1 I was impressed at what the cheaper, Growers choice 200 performed....I GUARENTEE I could run full-cycle with it and likely produce amazing end results....the 320w that the 300 puts out, together with newer technology, it should be a pretty awesome led......Glad to hear you like it so much....
You are both right and wrong. It is true no matter what because there are no such things as point sources. It is not a principle of physics but of math. If you have a flat sheet of LED's then, in fact, it is not flat but curved and the radius of curvature is just extremely large. It is equivalent to a very strong point source much further away. That is, you take a very large sphere and then some small "patch" on it will look flat but technically it is still part of a sphere. Even if it is irregular or convex things ultimately don't change. For all practical purposes you are right but technically you are wrong. For example, if you have one LED and it not being a laser but a sort of approximate point source with more than half of it's back side covered up then it will send light through a solid angle(a cone rather than a cylinder) and so the light sill spread out with the square of the distance but most of it will be contained, after some meters, still within a usable range. E.g., it is just a flashlight(flashlight beams still spread out, in fact have to so they are useful). If you have many LED's in a grid then this too happens but each LED compensates for losses to the next one as the "cones" cross. Just think of a grid of flashlights. This effectively increases the radius of curvature of the "equivalent" point source. It happens for anything, not just light. Sound also will have the effect as will anything that emits things. Again, it is a mathematical principle. The inverse square law has to do with the entire sphere(you integrate over the radius/surface) but if you are doing a patch it will depend on the curvature or radius(essentially the "same"(curvature = 1/r)). I'd show the math but I doubt anyone here would understand basic integral calculus. The idea though is very simple. If you have a fixed amount of "stuff" and you spread it out over the surface of a sphere(think of, say, paint or dough or fabric) and you doubled the radius of the sphere(reduced the curvature by 2) then you'd need 4x the amount of material(or you'd end up being able to cover only 1/4 of the larger sphere or have only 1/4 the thickness to cover it(for dough, paint, etc)). The only difference is that the "inverse square law" is a statement about the entire sphere while a flat panel is a statement about patch on the sphere. Ultimately though it's the same(since a sphere is made of patches and a patch is a part of a sphere) but just different perspectives and the practical aspects are different. Even if you have a very irregular surface that is not smooth, it doesn't change the fact that the more spread out something becomes the less dense it becomes(which is all the inverse square law is saying but it's a statement about it on spheres).
There's are laws and there are theories. If you say one of the laws are wrong then you are wrong. Please don't encourage science deniers. But instead you say it doesn't apply I'll add doesn't apply "the way people may think it should." But forget philosophy... Sides and multiple sources are good. Sides: when you raise the light, the distance reflections travel in proportion are less. That effect is squared. Probably a greater contribution is that as the angle of those reflected rays gets smaller then the sensor is seeing more photons because they are coming from closer to the center of the led where the lens is concentrating them. It's probably easier to understand in the case of the multiple LED fixture in open space. Start with the sensor close under the middle LED. The side leds are farther away. When you raise the leds they all get farther away but, in proportion, the LED distance in the center changes faster in proportion so using the center LED as the metric, the contribution of the edge LEDs does not diminish as fast. And likewise, light from the edge LEDs will actually increase when the fixture is raised because the angle to the sensor will take light from brighter and brighter parts of the lens. The advantages of angles and optics however are still diminished by the inverse square law... It's that when you raise the light you are squaring different things than when the light is lower. And yes, ISL apples to multiple point sources. Think "all light is photons" and classical and quantum physics will get the same results calculating one photon as a million trillion trillion... the results add up. Science laws aren't like people laws. They are very hard to break. So instead of suggesting that the ISL doesn't apply, I think it's more likely to say that it does apply but just not in the obvious way.
Hello I'm a new grower using the Sayhon SH4000 in a 28"×55"×80 tent... Have you guys checked this light out yet? if so what episode and if not could you test it. So far I like it id like to know what the pros think. ✌🏿
Its just like everything else in physics, the inverse square law works on an ideal point of light source (which can't exist), just like a friction-less pulley or other ideal physics scenarios.
frictionless pullies etc. are used to simplify problems for learning purposes and aren't used for actual engineering/ physics problems guy. In real life and advanced physics courses they dont used frictionless pullies and all measurable variables are accounted for, pal.
@@CarrotCakeMake I guess you never took a college physics class then where nearly everything you calculate is like this. Lets take a simple rope, pulley, and mass example. You could have more than hundreds of variables impacting the actual real world result of what you are testing.
Once again, I come away from one of your videos with good information, but also with more questions. I'll try to make this short. Considering the canopy penetration, I assume, and I think I remember you stating that LED bar and quantum boards are good because of the many light sources and angles. So, it seems to me that 1) more diodes are better than less, 2) the closer to the canopy would provide better angles, therefore being better. If the are true, then would more lower power LED's placed closer be better than stronger ones, providing equal par values at the top of the canopy? Maybe more, cheaper lower power diodes would be better than less higher powered ones ? Or, more higher powered ones running at less power? I am thinking in terms of results and efficiency. I hope that I made sense and you can understand what I am trying to say. Any input about this will be very much appreciated. Koi
it all holds true but more leds will just cost more the fixture will be bigger harder to make harder to transport. most use the very efficient samsung leds only real difference between most fixtures nowadays is how many they run the cooling solution and how much current they run trough them. some use 100 leds run 3 watt each some run 300 leds 1 watt each yea the 300led one generally will be better but way more expensive
Inverse square law apply as is only for point source that has omnidirectional radiation... If you have directed output, you must have gain function calculated in, this is basic EM stuff....
The fact, nonetheless is that the inverse square law accufately describes the behavior of unreflected light, not collimated nor reected. Please do not muddy the water by not being clear on this.
I thought he was being clear on that in the beginning of the video, when he described the law and said why growlights was different from what the law talks about.
So where would the inverse sq. Law work because as far as I can tell the theory isn’t quite sound….. it didn’t take into account density of the atmosphere in any given place …. Great video love comprehensive arguments
Its a property of light. This guy is propagating bad science. By his standard if i put any two lights in a small reflective area the law would not apply because measurements taken do not show it clearly. Fact is if you measure multiple light sources like the LED you will have inaccurate measurements, each diode must be measured individually to see the law in effect. While HPS appears to be direct light the end of the bulb refracts light in inconsistent patterns.
Is LEDs a lambertian source. Or is that only with diffused lighting. And LEDs are are on a plane which kinda scatters light in all directions would having LEDs chips that are say shaped around a type of tube or something having better coverage than the traditional flat potted in LEDs. Like example the in house made chips by Green Sunshine company don’t sit flat on a board they are kinda rounded.
What’s up there Shane was going to get a new led light and was looking at the gro pro 850 from grow light science and your 12 light package from migro and was wondering which of the two would be best for a 5x5
LED spectrum vs CMH (HID) is not linear. My plants know this however your quantum meter does not. Don’t forget that Apogee sensor can only measure par. According to Bugbee, there are sensors for HID and another for LED. The two are not interchangeable. I’m sorry friend, your test is flawed. The CMH was not deployed correctly while the LED was utilized as engineered. Reds penetrate more than blues, fact. CMH spectrums are much more consistent in spectrum make up than the average LED fixtures available these days. UV and far red are present in most CMHs. Most LEDs on the other hand lack UVs and far reds. Try comparing different LED spectrums (by frequency)to determine light loss. Reds travel much farther as compared to blues. Not all LED fixtures share the same spectrum recipes. A spectrometer would be more accurate don’t you think? It’s the inverse LAW friend. Are you trying to change Physics? Consider light recipes as a limiting factor in grow lights. Intensity is ONLY PART OF THE EQUATION or have you forgotten about blurple, lol…Thank you for your entertaining and educational videos. Your efforts are much appreciated!!!✌️
Hey Shane, I think your title should say "Inverse square law DOESN"T APPLY for grow lighting". It doesn't apply for 2 major reasons: 1 As you say, Light beam focus. Example- take a flashlight and hold 1 foot away from the wall. Measure that circle (2"). Now back away to 2 feet and it looks dimmer until you refocus the lens back to the 2" then looks very close to original brightness. 2 Intensity matters. Example- 2 flashlight, 1 can shine on a wall 10 feet away the other can shine 50 feet away. the amount of loss at 5 feet away for the higher-powered light will be less. Canopy penetration refers to where the Larf starts. You can only get the light so close to the top without problems, so the depth of your good bud vs Larf will relate to the power of the light.
And how many miles apart are the two trains that left Brussels at different times in different directions...four hundred and twenty miles...420...A.C.Feuerhelm
Dang. I do know that with reflective walls, the PAR at 2 feet is generally 50% of PAR at 1 foot. Without reflective walls, it would be less than 50%. I didn't even go to 3 or 4 feet 😆 I just went by the grow conditions I'm looking to put together. I never had any physics. I did have college English 101 when I was a sophomore in High School though. 😐
Are you saying he should have measured at 1ft and 2ft from the canopy? With an 8" distance apart and Mylar walls there was only a 12.86% difference in PAR. Just wondering what wasn't explained or shown? I'm no genius, for sure! Any input would be great!👍
@@timturk1899 No. I'm saying I should have answered none of the above! I chose without reflective walls because of what I know about PAR levels with reflective walls at 2 feet and 1 foot. I did not stop to remember that the 2 and 1 rule I noticed really only applies to strong even coverage lights like the Atreum 3200 and Maxi MF2000 that I ended up buying.
Well as a X-ray tech your reflective wall are causing your test Results to be less accurate because with the LED you’re bouncing more scatter because LEDs cannot Collimate like your ceramic metal halide that’s why the CMH is closer to the inverse square law because I can collimate the primary be more directly
Thanks for bringing up these different topics. What is your take on the Photobio Quantum sensor? It’s the only one the local grow supply shop had and cost $170 US.
So, first your point about the reflective walls is a valid one since no material reflects 100% efficiently. However, the problem with your test is that your model of taking the average readings does not take into account basic Geometry. The Pythagorean Theorem (which cannot be disputed) states that an increase in length of the hypotenuse of a right Triangle A2 + B2 = C2 will not be linear unless you are increasing the length of both other legs of the right triangle evenly. Therefore, by doubling the height but not increasing the area of your grow space, you are not increasing the distance from the light to the edges of your canopy linearly. Now, the closer your light is dimensionally to the dimensions of your grow area the less this will influence those numbers (as your “B” leg of the triangle is shorter and will effect your sum less), but in this case you are using a very small light dimensionally compared to your space. So, let’s say we had 20cm height and the edge of your space was 40cm from a plum line drawn straight down from the edge of your light. That gives you a rough distance of 44.72 cm for your hypotenuse. Now, double that height to 40 cm but keep the other leg of the triangle the same and you get a 56.57 cm hypotenuse, not 80 cm. This drastically increases the complexity of a legitimate design that you would need to make averaging out the PPFD a worthwhile comparison. What you should do is just take a quantum sensor and place it directly under the light (use a level to be sure it’s plum if you really want to be accurate) and take a measurement. Then half or double the height of the light and take another measurement. I’ve done this with my light and it winds up more or less tracking pretty accurately in line with what the Inverted Square law predicts. Would like to see the specific measurements directly under the light were at these 2 hanging heights and see how they compare. Thanks for the video. ✌️
You are mesuring it wrong if 1 foot away is 100% then 2 feet is 25% you are also moving the meter around you cant get an acurate reading as the height will not be the same for each measurement place on the area and angle of light act.. but if you move the light away and keep the meter in the same place where ever that is on the grid that spot will lose 75% of the light it was from 1 foot away - 2 foot way. Moving the meter is not giving you a correct measurement as they are different spots. Uniformity and luminosity are different things. Draw 1million tiny cubes in 1x1m each and every one of those cubes will receive 75% less light every distance the light is doubled from the source cube 1 might have 300par cube 2000 might have 600 per if you move the light 1 foot away both cubes will lose 75% of the light luminosity.
Physical laws can not be broken otherwise it's no longer a physical law!!! That's a fact!!! Even inside a tent a with led bars the inverse swquare law is still valid you just have to calculate it for any single light source and need to take reflections into account. The whole discussion has started years ago and is just because of one single fact; the fight between HPS an LED users! Lets say we have a single light source like a 1000w HPS bulb and we measure intensity at 4ft and at 6ft distance because we plan to have 2ft tall plants we'll get readings of ~600μMol/s/m² and maybe 450μMol/s/m². That's because we are already farer away from the light source and the reducing effect gets smaller. If we use an LED strip fixture at the recommended hanging hight of 1,5ft and measure ~600μMol/s/m² intensity and measure intensity at 3,5ft the reducing effect is much higher and we only get ~300μMol/s/m². That's not because the inverse square law is no longer working inside a tent or with reflective walls it's just because of the usually higher distance we use with HPS lights. The whole penetration discussion is for the bin, both types of lights have pros and cons. One could replace a HPS light using a high power COB with 60-80° lens and you would see the same results at higher distances. Physical laws are called laws because they can't be broken!
Can you do this with a ball of light show these fools that the sun is not being reflected on the moon. They are two different energies. Thank you Shane
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the only man who's word I trust when it comes to anything related to lighting. big respect Migro, always extremely informative.
Also Dr Bruce Bugbee is another man who you should look into and trust when it comes to grow lights and plants/photosynthesis etc especially if you want a more in depth look into certain things. He’s done a lot of work with cannabis Lately too.
Migro is the man when it comes to grow light comparisons etc tho, That’s for sure.
Well then you should be trusting Dr Bruce bugbee because that is where Shane gets the majority of his information from
Well you should learn the difference between laws and theories.
If in fact anyone proves the law does not apply to specific light sources they would be in science journals for disproving a law.
It would only be a theory if any lights were found that did not adhere to the law.
He is misrepresenting facts as he misinterprets his readings.
@@swskitso actually, you are still using those words improperly from a scientific standpoint.
In Science, a Law (like the Law of Gravity or Newton’s Law of Thermodynamics) explains/predicts how objects (including things like light particles/photons) will behave within given conditions. It takes overwhelming amounts of objective data for something to become a Law in Science.
A Theory in Science is an explanation for how or why something occurs the way it does. For instance, the Theory of Gravity is our best current understanding of how Gravity works. In no way does it try to argue whether or not Gravity exists.
What Shane is offering here is neither a Theory, nor a Law, but instead a Hypothesis, which is a tentative statement/idea about the natural world which can then be tested and either corroborated or proven false. Unfortunately for him, his experimental design is flawed and so does not show what he originally thought it did and so in no way disproves the Inverted Square Law (and as you said, disproving of an actual Scientific Law would lead to a truly monumental shift in Scientific understanding and our paradigm about the world around us and would put your name all over the Scientific community). ✌️
but knows nothing lol sales man yes physics no
Finally, Shane's take on inverse square law. So much controversy on this subject. Love how u break it down to "actual" science and laws that we can understand without needing a degree👍 nicely done Migro👏
Actual science would show the inverse square law in effect but by measuring multiple light sources from the LED its an inaccurate measurement and measuring indirect light from the HPS is inaccurate as well.
This is terrible science.
Except it is wrong.
@@swskitso yes he's missed the point of law lol. but nice try migro...
By Controversy you mean a bunch of internet back seat experts who never tested anything in their life parroting dogma they read.
@@swskitso You completely missed the point you donut. This isn't setting out to disprove the law, it's setting out to disprove its applicability when discussing grow light heights. Internet experts incorrectly assume that doubling the height of a grow lamp will 1/4 the light output reached to the plants. This is incorrect.
What a great video. While of course the inverse square law holds true as a pure physics/geometry exercise, as you show there are multiple reasons that the inverse square law doesn't hold up in a grow room application. Well done.
It does hold up but you cant expect accurate readings from multiple light sources or indirect light.
@@swskitso
Agreed.
It drives me nuts that he keeps saying the law dont apply.
Its a misrepresentation of the facts.
@@swskitso
Certainly the law doesn't apply the most people apply it - not even close, which is the point.
If he accounted for the fluence map through geometric parameters we would see inverse square. This would account for gradients and spatial variance of fluence, which is not needed in the case of isotropic radiation from a point source.
Thank you Shane for the work you do for us! The time and energy you sacrificed to perform the experiments and give real data is extremely appreciated here!
One thing that was left out was the effect of the shape of what is receiving the light. A sphere will see much more of a consistent drop off compared to a flat object like a leaf. A leaf close to the center of a light bar is getting very little light from distant diodes, but when you back up a leaf it is then collecting much more from distant diodes. In some cases it can get brighter as you back away.
Obstruction---a topic ive never seen really debated or testet on UA-cam. The smaller your source of light, the more leaves wont get direct light. the perfect panel would cover 90% of the complete surface, only allowing some air to pass by. I think this is even more important than the naked efficiency. It is another form of efficiency. Efficiency on paper can be deceiving. take a cob for example. The light is distributed well if its high enough. At least on paper and on the sensor. But once the canopy grows and is not levelled anymore, many leaves will block other leaves from direct light, because the source is so small.
Thanks again for the great content and info. My whole growing mindset has changed since I started watching your channel. Par meters, I now understand, tell the real story about what my plants are receiving. Now I know if something is wrong in the grow room that it's not the lighting. Happy growing all. Go Shane!
I would to see Shane take his light spectrum meter outside on cloudy days and see how clouds effect the
light spectrum. Which colors are lost most in the clouds. I have a lux meter that I convert to PAR. If the clouds
are real white and you have to squint is is around 600. As soon as the clouds have any gray to them
the par goes from 100 to 50.
Truth can never be hidden,,well done my man.
People need to understand that with most "laws" the theoretical will hardly ever match the practical, too many variables in real life.
To include not deploying the cmh as intended vs the led as engineered. AND… using the same quantum sensor to measure the par. Hid sensors are different than led sensors according to Bruce Bugbee✌️
I just imagined light speed travel with the help of your comment. It'll be possible but not weird or however we've imagined it in scifi etc.
And aye im totally serious. Id never thought about theories and facts concerning physics. Im just rambling. Love you, Shane, and Migro 🖖🖖🖖
When you measure multiple light sources or indirect light yes there are too many variables for an accurate measurement.
Thats exactly what i tried telling the officer but he wasn't having it ....🌱🌱👮👮🚓🚓🚓🚓🚨🚨
@@jayo8621 that's what the court room is for you don't try to convince the officer they already made up their minds.
Everybody’s grow space does not have the same reflective material that you use so when you test your lights you’re in fluctuating the numbers because of your reflective test area when I tested x-ray machines we didn’t test with the scattering
Weird that you didn't put a reflector on the cmh for this test 🤔
I’m happy to see this video being made. I see people in massive facilities getting light lifters when in reality they have a lit plane so it makes little to no difference how high they put their lights. It’s hard to convince people of that.
Many of us measure with a cell phone app that is different from a genuine par meter because it's lens is more flat and directional than the semicircular lens of the par meter.
120 degree angle measurement with a phone app is important for getting light penetration into the sides of a plant is an important measurement this video ignores causing many people to miscalculate the shape and underestimate the usable size of their lighting footprint.
Bruce sells Apogee so he also excuses this measurement which is a valuable tool for decisions.
Hi,
The phone apps vary in accuracy based on the phone and camera used.
Thanks.
my whole living room....full of houseplants n such...loves the aray 2...what im saying is...all the plants in every corner...are thriving
Shane …. Wondering if you could please do this test …. An old photographer’s trick to calculating light. It’s based on cameras f/ stops which are converted to inches, feet, yards whatever. So there’s f/2, f/2.8, f/4, f5.6, f/8, f/11, f/16, f/22
So for our example f/16 = 16” from light to canopy. When you raise the light to 22” the reading should be 1/2 the amount, theoretically anyway.
Would this be an interesting quick test for you to try ??
Thanks for all your content
Awesome content,I'm not a book smart 52 yrs old man an understood it, great video
What's a book?
The inverse square law is just a fact of life. Your measurements are not disproving anything. When you double the distance of the array only the diode directly above the sensor will have 1/4 the photon flux density. All other diodes in the array will not have moved double the distance from the sensor thus will not have 1/4 the pfd.
Love the work man always with the scientific viewpoint without being convoluted. Keep it up!
Scattered par from reflective material is not true primary beam energy is lost from the light photons twhen it’s redirected to the primary source but scatter will raise density numbers but is not the primary beam plus the inverse square law does not have reflection in the diagram and is based on the fact all photons 100% primary beam are in the equation that is I physically impossible to do
Inverse square law is just a basic law like gravity but we all hit terminal velocity at different speeds
Inverse square law is more accurate when testing a single light source unlike leds with multiple lights of course inverse square law gets thrown out the window when scatter light photon from reflection are used in the equation that’s why your more closer too the inverse square with out the reflection walls creating noise inverse square is accurate when the testing is more actually done
Haha. Love the way you respond to folks. Your channel rocks Shane ✌🏻
Are you going to tell us how this redefines light penetration?
Great vid tks Shane i still run hid , and don't most hid users run bulb with reflector and to my understanding better light with bulb horizontal
The inverse square law is not wrong. You are just using an integral of inverse square laws. Just because planes can fly doesn't make gravity theory wrong.
Thats all gravity is, a theory. Never been proven to be a force. Was replaced 107 years ago with Einstein gravity - Not a force. None of these gravity theories have ever been proven to exist. They are just stories that brainwashed people believe in. 😎
I think this is consistent with your light penetration ideas. Nice. Thanks!
Thank you for all you do.
You gotta know Shane the BRO science is rampant in the growers community.
Decrease the object image distance OID or move the light down you will i crease the intensity so yea it is correct the theory of the inverse square law it just does not work in real life due too other influences like air resistance to gravity
Thanks for this…I recently added a second light thinking it would b twice as good… I ended up burning every plant 🌱..!!!
Thank you.....for ALL YOU DO !
YOU....are the GO-TO SOURCE, AT least for myself, when researching which led to invest in......I recently purchased the Grow Light Science 300 , to replace my CMH , in my vegetation sector...which I am hesitant, as I propagate/pre-veg under the Growers Choice ROI-200...which as a Full-spectrum w far red , CREATING MASSIVE BRANCHING.....the CMH is a more blue leaning spectrum which grows strength and stretch..... which sets me up for an AWESOME bloom cycle under an HLG-600R and the PHOTONTEK-600PRO......The results are AMAZING....
Thanks again , sooo much for ALL you do as you have been an extremely valuable ASSET to me....Thank you !
i bought the 300 late last year, so far its awesome
@@simonaek1 I was impressed at what the cheaper, Growers choice 200 performed....I GUARENTEE I could run full-cycle with it and likely produce amazing end results....the 320w that the 300 puts out, together with newer technology, it should be a pretty awesome led......Glad to hear you like it so much....
That was awesome as always brother. 👏 I understood completely and my only light knowledge comes from you and Dr Bruce. Makes perfect sense
You are both right and wrong. It is true no matter what because there are no such things as point sources. It is not a principle of physics but of math. If you have a flat sheet of LED's then, in fact, it is not flat but curved and the radius of curvature is just extremely large. It is equivalent to a very strong point source much further away. That is, you take a very large sphere and then some small "patch" on it will look flat but technically it is still part of a sphere. Even if it is irregular or convex things ultimately don't change. For all practical purposes you are right but technically you are wrong.
For example, if you have one LED and it not being a laser but a sort of approximate point source with more than half of it's back side covered up then it will send light through a solid angle(a cone rather than a cylinder) and so the light sill spread out with the square of the distance but most of it will be contained, after some meters, still within a usable range. E.g., it is just a flashlight(flashlight beams still spread out, in fact have to so they are useful).
If you have many LED's in a grid then this too happens but each LED compensates for losses to the next one as the "cones" cross. Just think of a grid of flashlights. This effectively increases the radius of curvature of the "equivalent" point source.
It happens for anything, not just light. Sound also will have the effect as will anything that emits things. Again, it is a mathematical principle. The inverse square law has to do with the entire sphere(you integrate over the radius/surface) but if you are doing a patch it will depend on the curvature or radius(essentially the "same"(curvature = 1/r)).
I'd show the math but I doubt anyone here would understand basic integral calculus. The idea though is very simple. If you have a fixed amount of "stuff" and you spread it out over the surface of a sphere(think of, say, paint or dough or fabric) and you doubled the radius of the sphere(reduced the curvature by 2) then you'd need 4x the amount of material(or you'd end up being able to cover only 1/4 of the larger sphere or have only 1/4 the thickness to cover it(for dough, paint, etc)).
The only difference is that the "inverse square law" is a statement about the entire sphere while a flat panel is a statement about patch on the sphere. Ultimately though it's the same(since a sphere is made of patches and a patch is a part of a sphere) but just different perspectives and the practical aspects are different. Even if you have a very irregular surface that is not smooth, it doesn't change the fact that the more spread out something becomes the less dense it becomes(which is all the inverse square law is saying but it's a statement about it on spheres).
I'm in Australia, it'll be expensive, but God damn if my next light, and all the rest from then on, will be a Migro light for sure.
There's are laws and there are theories. If you say one of the laws are wrong then you are wrong. Please don't encourage science deniers. But instead you say it doesn't apply I'll add doesn't apply "the way people may think it should." But forget philosophy... Sides and multiple sources are good. Sides: when you raise the light, the distance reflections travel in proportion are less. That effect is squared. Probably a greater contribution is that as the angle of those reflected rays gets smaller then the sensor is seeing more photons because they are coming from closer to the center of the led where the lens is concentrating them. It's probably easier to understand in the case of the multiple LED fixture in open space. Start with the sensor close under the middle LED. The side leds are farther away. When you raise the leds they all get farther away but, in proportion, the LED distance in the center changes faster in proportion so using the center LED as the metric, the contribution of the edge LEDs does not diminish as fast. And likewise, light from the edge LEDs will actually increase when the fixture is raised because the angle to the sensor will take light from brighter and brighter parts of the lens. The advantages of angles and optics however are still diminished by the inverse square law... It's that when you raise the light you are squaring different things than when the light is lower. And yes, ISL apples to multiple point sources. Think "all light is photons" and classical and quantum physics will get the same results calculating one photon as a million trillion trillion... the results add up. Science laws aren't like people laws. They are very hard to break. So instead of suggesting that the ISL doesn't apply, I think it's more likely to say that it does apply but just not in the obvious way.
Hello I'm a new grower using the Sayhon SH4000 in a 28"×55"×80 tent... Have you guys checked this light out yet? if so what episode and if not could you test it. So far I like it id like to know what the pros think. ✌🏿
Its just like everything else in physics, the inverse square law works on an ideal point of light source (which can't exist), just like a friction-less pulley or other ideal physics scenarios.
Perpetual motion machines are real! The earth is flat! Birds aren't real!
frictionless pullies etc. are used to simplify problems for learning purposes and aren't used for actual engineering/ physics problems guy. In real life and advanced physics courses they dont used frictionless pullies and all measurable variables are accounted for, pal.
There's no such thing as "ideal physics". Theories of mechanics don't stop working because there is friction, that is just an extension of the theory.
@@CarrotCakeMake I guess you never took a college physics class then where nearly everything you calculate is like this. Lets take a simple rope, pulley, and mass example. You could have more than hundreds of variables impacting the actual real world result of what you are testing.
@@jacobstanfill9538 That is what I was saying...
Once again, I come away from one of your videos with good information, but also with more questions. I'll try to make this short. Considering the canopy penetration, I assume, and I think I remember you stating that LED bar and quantum boards are good because of the many light sources and angles. So, it seems to me that 1) more diodes are better than less, 2) the closer to the canopy would provide better angles, therefore being better. If the are true, then would more lower power LED's placed closer be better than stronger ones, providing equal par values at the top of the canopy? Maybe more, cheaper lower power diodes would be better than less higher powered ones ? Or, more higher powered ones running at less power? I am thinking in terms of results and efficiency. I hope that I made sense and you can understand what I am trying to say. Any input about this will be very much appreciated. Koi
it all holds true but more leds will just cost more the fixture will be bigger harder to make harder to transport. most use the very efficient samsung leds only real difference between most fixtures nowadays is how many they run the cooling solution and how much current they run trough them. some use 100 leds run 3 watt each some run 300 leds 1 watt each yea the 300led one generally will be better but way more expensive
Inverse square law apply as is only for point source that has omnidirectional radiation...
If you have directed output, you must have gain function calculated in, this is basic EM stuff....
Very interesting 🧐
Multi source lighting does not affect inverse square law at all.
hello shawn, will the Maxsisun-Sale still be going on next week? Id like to buy a lamp for someone but we can only order at 01.06.?? I hope so
I learn something new every time I watch one of your videos
The fact, nonetheless is that the inverse square law accufately describes the behavior of unreflected light, not collimated nor reected. Please do not muddy the water by not being clear on this.
I thought he was being clear on that in the beginning of the video, when he described the law and said why growlights was different from what the law talks about.
So where would the inverse sq. Law work because as far as I can tell the theory isn’t quite sound….. it didn’t take into account density of the atmosphere in any given place …. Great video love comprehensive arguments
I always thought the inverse square law was due to a property of light. I never realized it was due to the 360 degree radiation. Makes more sense now.
Its a property of light.
This guy is propagating bad science.
By his standard if i put any two lights in a small reflective area the law would not apply because measurements taken do not show it clearly.
Fact is if you measure multiple light sources like the LED you will have inaccurate measurements, each diode must be measured individually to see the law in effect.
While HPS appears to be direct light the end of the bulb refracts light in inconsistent patterns.
@@swskitso I guess his test equipment is wrong too?
Is LEDs a lambertian source. Or is that only with diffused lighting. And LEDs are are on a plane which kinda scatters light in all directions would having LEDs chips that are say shaped around a type of tube or something having better coverage than the traditional flat potted in LEDs.
Like example the in house made chips by Green Sunshine company don’t sit flat on a board they are kinda rounded.
Great video I’ve learned so much about grow lights since watching and subscribing to your channel
His data set proves the law. However shows reflective surfaces help bounce light (surprise)
Thank you for this my friend, great video as always 💪💪💪🙏🙏🙏🙌🙌🙌💚💚💚
Thank you, Shane. It really explains the importance of reflective walls.
Nothing like real world experiences, way to go breaking that down!
great stuff shane
Those are indeed surprising test results.
What’s up there Shane was going to get a new led light and was looking at the gro pro 850 from grow light science and your 12 light package from migro and was wondering which of the two would be best for a 5x5
LED spectrum vs CMH (HID) is not linear. My plants know this however your quantum meter does not. Don’t forget that Apogee sensor can only measure par. According to Bugbee, there are sensors for HID and another for LED. The two are not interchangeable. I’m sorry friend, your test is flawed. The CMH was not deployed correctly while the LED was utilized as engineered. Reds penetrate more than blues, fact. CMH spectrums are much more consistent in spectrum make up than the average LED fixtures available these days. UV and far red are present in most CMHs. Most LEDs on the other hand lack UVs and far reds. Try comparing different LED spectrums (by frequency)to determine light loss. Reds travel much farther as compared to blues. Not all LED fixtures share the same spectrum recipes. A spectrometer would be more accurate don’t you think? It’s the inverse LAW friend. Are you trying to change Physics? Consider light recipes as a limiting factor in grow lights. Intensity is ONLY PART OF THE EQUATION or have you forgotten about blurple, lol…Thank you for your entertaining and educational videos. Your efforts are much appreciated!!!✌️
Hey Shane, I think your title should say "Inverse square law DOESN"T APPLY for grow lighting".
It doesn't apply for 2 major reasons:
1 As you say, Light beam focus. Example- take a flashlight and hold 1 foot away from the wall. Measure that circle (2"). Now back away to 2 feet and it looks dimmer until you refocus the lens back to the 2" then looks very close to original brightness.
2 Intensity matters. Example- 2 flashlight, 1 can shine on a wall 10 feet away the other can shine 50 feet away. the amount of loss at 5 feet away for the higher-powered light will be less.
Canopy penetration refers to where the Larf starts. You can only get the light so close to the top without problems, so the depth of your good bud vs Larf will relate to the power of the light.
I love you videos although I don’t understand it all I use a small invisible sun light and really like it but I’ve never seen you review one
you should try the same test at further distances. 80 cm, 160 cm.
Brilliant 🤩 thanks for breaking that down for us in a way that we can understand
Can you plz do a lucius flex r 680w light review
Claims ppf 3.5 mol/j & output of 2380 umol/s
Thnx
And how many miles apart are the two trains that left Brussels at different times
in different directions...four hundred and twenty miles...420...A.C.Feuerhelm
Does the inverse square law apply to the sun?
Good to hear but that was never any of my concerns anyways.
I can measure light intensity.
Be lost without you Shane 👏👏
Bro. This is an amazing video. Thank you
Dang. I do know that with reflective walls, the PAR at 2 feet is generally 50% of PAR at 1 foot. Without reflective walls, it would be less than 50%. I didn't even go to 3 or 4 feet 😆 I just went by the grow conditions I'm looking to put together. I never had any physics. I did have college English 101 when I was a sophomore in High School though. 😐
Are you saying he should have measured at 1ft and 2ft from the canopy? With an 8" distance apart and Mylar walls there was only a 12.86% difference in PAR.
Just wondering what wasn't explained or shown? I'm no genius, for sure! Any input would be great!👍
@@timturk1899 No. I'm saying I should have answered none of the above! I chose without reflective walls because of what I know about PAR levels with reflective walls at 2 feet and 1 foot. I did not stop to remember that the 2 and 1 rule I noticed really only applies to strong even coverage lights like the Atreum 3200 and Maxi MF2000 that I ended up buying.
Well as a X-ray tech your reflective wall are causing your test Results to be less accurate because with the LED you’re bouncing more scatter because LEDs cannot Collimate like your ceramic metal halide that’s why the CMH is closer to the inverse square law because I can collimate the primary be more directly
These lights have ..20-30 cm distance between them? hmmm
Thanks for bringing up these different topics. What is your take on the Photobio Quantum sensor? It’s the only one the local grow supply shop had and cost $170 US.
Noy sure, I'll have a look at it, thanks Shane
It works great. For the home grower it’s a much more sensible value than an apogee.
My favourite type of videos
Shane, am I not mistaken and you are high?
Thanks. Appreciate your sharing of knowledge.
Thank you, I like your personality and knowledge.
This video may come just in time to save people from being anti-science.
Anti science would be claiming the law does not apply to lights because of poor test methods.
@@swskitso Justin?
Thanks
Shane needs an unintentional ASMR channel lol
Great video, Shane, thanks
thanks for putting us straight ..😎
Excellent informational video. Really appreciate the time and effort you put into these videos to help educate us.
So, first your point about the reflective walls is a valid one since no material reflects 100% efficiently.
However, the problem with your test is that your model of taking the average readings does not take into account basic Geometry.
The Pythagorean Theorem (which cannot be disputed) states that an increase in length of the hypotenuse of a right Triangle A2 + B2 = C2 will not be linear unless you are increasing the length of both other legs of the right triangle evenly.
Therefore, by doubling the height but not increasing the area of your grow space, you are not increasing the distance from the light to the edges of your canopy linearly.
Now, the closer your light is dimensionally to the dimensions of your grow area the less this will influence those numbers (as your “B” leg of the triangle is shorter and will effect your sum less), but in this case you are using a very small light dimensionally compared to your space.
So, let’s say we had 20cm height and the edge of your space was 40cm from a plum line drawn straight down from the edge of your light. That gives you a rough distance of 44.72 cm for your hypotenuse.
Now, double that height to 40 cm but keep the other leg of the triangle the same and you get a 56.57 cm hypotenuse, not 80 cm. This drastically increases the complexity of a legitimate design that you would need to make averaging out the PPFD a worthwhile comparison.
What you should do is just take a quantum sensor and place it directly under the light (use a level to be sure it’s plum if you really want to be accurate) and take a measurement. Then half or double the height of the light and take another measurement.
I’ve done this with my light and it winds up more or less tracking pretty accurately in line with what the Inverted Square law predicts.
Would like to see the specific measurements directly under the light were at these 2 hanging heights and see how they compare.
Thanks for the video. ✌️
Brilliant
I will definitely share
Well said shane
You are mesuring it wrong if 1 foot away is 100% then 2 feet is 25% you are also moving the meter around you cant get an acurate reading as the height will not be the same for each measurement place on the area and angle of light act.. but if you move the light away and keep the meter in the same place where ever that is on the grid that spot will lose 75% of the light it was from 1 foot away - 2 foot way. Moving the meter is not giving you a correct measurement as they are different spots. Uniformity and luminosity are different things. Draw 1million tiny cubes in 1x1m each and every one of those cubes will receive 75% less light every distance the light is doubled from the source cube 1 might have 300par cube 2000 might have 600 per if you move the light 1 foot away both cubes will lose 75% of the light luminosity.
I’m lucky, I bought the sexy Migro 600, it’s a circle, lol.
super helpful , thanks
Bravo! Well done.
That’s great news!!!
Good Information thanks!!
Physical laws can not be broken otherwise it's no longer a physical law!!! That's a fact!!! Even inside a tent a with led bars the inverse swquare law is still valid you just have to calculate it for any single light source and need to take reflections into account.
The whole discussion has started years ago and is just because of one single fact; the fight between HPS an LED users!
Lets say we have a single light source like a 1000w HPS bulb and we measure intensity at 4ft and at 6ft distance because we plan to have 2ft tall plants we'll get readings of ~600μMol/s/m² and maybe 450μMol/s/m². That's because we are already farer away from the light source and the reducing effect gets smaller.
If we use an LED strip fixture at the recommended hanging hight of 1,5ft and measure ~600μMol/s/m² intensity and measure intensity at 3,5ft the reducing effect is much higher and we only get ~300μMol/s/m². That's not because the inverse square law is no longer working inside a tent or with reflective walls it's just because of the usually higher distance we use with HPS lights. The whole penetration discussion is for the bin, both types of lights have pros and cons. One could replace a HPS light using a high power COB with 60-80° lens and you would see the same results at higher distances. Physical laws are called laws because they can't be broken!
Great video, I never knew
Can you do this with a ball of light show these fools that the sun is not being reflected on the moon. They are two different energies. Thank you Shane
please dont breed
Sometimes mis-led. Sorry, I’ll get me coat
😆
Umm...the law itself still applies though...
Shane the MythBuster?! Just add a few fancy explosions and we are all good 😀
Thank you for the informative video, sir!
Wena info siempre bien migro
One for the algorithm. Cheers!
Shane come and be Australia’s first truthful prime minister.
You do the work of God. Thanks again
Lol there aren’t a lot of Mylar walls in space.