Everything in this post applies to an isotropic light source like a light bulb. An LED is nothing like a light bulb. An LED is more complex. An LED is not isotropic where the light radiates in all directions at the same intensity. An LED radiates at various intensities as shown in their datasheet's Spacial Radiation Distribution. Also called
Bridgelux: Radiation Pattern
Cree: Spacial Distribution
Citizen: Radiation Characteristic
Luminus: Radiation Plot
Lumiled: Radiation Pattern Characteristics
No, you can't. Only a complete noob thinks that is feasible.
It's simple Inverse Square Law being used the way it is supposed to be used.
Doesn't work huh? OK, lets have the deluge of excuses why you are still "right"
Inverse square certainly did work, those numbers were generated using Inverse Square Law. Just go back and look at the code. Just becasue you do cannot grasp what I did there. Your ignorance is astounding.
This is simple shit. Why do you not understand????
Doesn't work huh? OK, lets have the deluge of excuses why you are still "right"
Here, your own list of measurements. Just calculate all of these back to the "standardized 1 meter distance PPFD":
ements.
See below, Step 1 of instruction on how to convert lm to lx. That "standardized 1 meter" is exactly how it is done!!!!!!!!!
Below is from an 8/18/2016 email where that data came from.
This line of code IS the Inverse Square Law:
$lux = pow($ref/$distance,2) * $intensity[$angle];
You are wrong because you understand none of what you are saying. It's not as bad anymore as when you couldn't keep track of what was "moles" and lumen (while you were doing spot PPFD measurements and inverse square correcting them to 1 meter distance).
Notice in the example below how step one normalizes irradiance at 1 meter!!!!
Yes of course that's true. Although I said: "average PPFD = PPF minus wall losses / surface area".
What's your "surface area"? Grow Area?
That would work if you had the distance to your "surface area"
The following example is lm to lux but it will work the same for PPFD to PPF.
Just reverse the process to get PPF to PPFD. Although there is an easier way if you can understand how the example does the conversion. Yu can use
The following lx to lm conversion is from a free download: https://www.intl-lighttech.com/ilt-light-measurement-handbook.
Does the above example look like your "average PPFD = PPF minus wall losses / surface area"?
Actually it almost does depending on what you call "surface area". Where the 30° would be the equivalent of your "wall loses". r is the distance.
In my next post I will show you an easy way to estimate PPF to PPFD but without "wall losses".
You first need to learn a few things.
If you want to see where LED datasheets get flux, here is a link to how Lumiled suggests to measure LED flux in this White Paper: Optical Measurement Guidelines
https://www.lumileds.com/uploads/377/WP17-pdf
I have also attached a PDF, chapter 24 "Optical Measurements, Radiometry and Photometry" from the book "Handbook of Optics". It has all the information necessary to calculate an energy transfer (i.e. conversion).
https://www.amazon.com/002-Handbook-Devices-Measurements-Properties/dp/0070479747/
In the PDF I highlighted, in yellow, the areas where I believe you are confused about distance and surface area.
PPF (flux) to PPFD (irradiance) is explained in radiometric terms in Section 24.4 RADIANT TRANSFER APPROXIMATIONS.
A = 4πr²
