How to Plot PPF Chart with Quantum Sensors for LED light comparison

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PurpleBuz

Well-Known Member
I'm still impressed with square khatod,, incredibly even coverage, but agree looks like the spread is too wide.
Looking through numerous ledil datasheets, its apparent that the size of the LES makes a difference on the focus of the lens. I'd be curious to see this compared to a smaller cob (like a 3070 or vero 18 8) if you have one handy.

Thanks for sharing!
 
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robincnn

robincnn

Well-Known Member
@PurpleBuz
I also saw LEDIL charts with different cobs and it seems the LES is pretty important.
Did not have time to do a PAR measurement setup again. Also it might not help much as the spread is too wide.
I do have a Vero 10 but in 5000k. But its too small compared to the lens. On website they say its good for vero 13 to 29
20151001_183043.jpg

Here are some photos as 4.5 inches from wall. With Vero 10 300ma the spread was around 20 inches (too much spread)
Not apparent in photo but the center was dim and looks like most light was focused on a narrow square outer band. Looks a little wider spread with smaller LES
Vero10.jpg

With Vero 29 at 300ma
The light was more even. Notice how the outer band is much wider
Vero 29.jpg

So yes these optics are designed for specific range of LES.
The larger glass lens like 100mm would be much more forgiving.
 
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robincnn

robincnn

Well-Known Member
All my charts prior to khatud were PAR sensor angled towards the COB.
With recent khatud test sensor was vertical
Also I keep ambient light low (under 1PPF) to avoid errors. Non reflective area

I have attached my chart template incase anyone finds it helpful.
In charts the average is not just the average of all numbers. The number in the center are less important as they serve a smaller area and outer numbers more important as they serve a larger area. No clue right now but I will see if I can add a calculation within the excel later.
Thanks
 

Attachments

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PurpleBuz

Well-Known Member
robincnn said:
@PurpleBuz
I also saw LEDIL charts with different cobs and it seems the LES is pretty important.
Did not have time to do a PAR measurement setup again. Also it might not help much as the spread is too wide.
I do have a Vero 10 but in 5000k. But its too small compared to the lens. On website they say its good for vero 13 to 29
View attachment 3512119

Here are some photos as 4.5 inches from wall. With Vero 10 300ma the spread was around 20 inches (too much spread)
Not apparent in photo but the center was dim and looks like most light was focused on a narrow square outer band. Looks a little wider spread with smaller LES
View attachment 3512120

With Vero 29 at 300ma
The light was more even. Notice how the outer band is much wider
View attachment 3512121

So yes these optics are designed for specific range of LES.
The larger glass lens like 100mm would be much more forgiving.
Click to expand...
the pics show the effect of les size quite nicely. ty.
 
robincnn

robincnn

Well-Known Member
@alesh
It came with a cover. Fits very well. They say in datasheet 'NO need for extra protection: glass or gasket for IP.

Khatod is like a hard 'Ultra Clear Silicone Optic' and flexible on sides
Ledil Stella is softer/flexible all over. Dust sticks easily on Ledil.
Khatod looks better engineered than Ledil.No idea about price


upload_2015-10-15_22-25-52.png
upload_2015-10-15_22-26-55.pngupload_2015-10-15_22-27-37.pngupload_2015-10-15_22-27-13.png

Edit: I think they also make a holder for cobs. I dont have those holder.
upload_2015-10-15_22-51-1.png
 
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alesh

alesh

Well-Known Member
robincnn said:
@alesh
It came with a cover. Fits very well. They say in datasheet 'NO need for extra protection: glass or gasket for IP.

Khatod is like a hard 'Ultra Clear Silicone Optic' and flexible on sides
Ledil Stella is softer/flexible all over. Dust sticks easily on Ledil.
Khatod looks better engineered than Ledil.No idea about price


View attachment 3522037
View attachment 3522038View attachment 3522040View attachment 3522039

Edit: I think they also make a holder for cobs. I dont have those holder.
View attachment 3522054
Click to expand...
Thanks great info. So you just screw down the cover through the (4) mounting holes?
 
AquariusPanta

AquariusPanta

Well-Known Member
robincnn said:
@alesh, yes the cover can be mounted with the 4 screws.
Ledil mounts similarly. Photo on previous page.

A note about my Ledil testing on previous page.
The results were at 18 inches and not 12 inches as listed on my post.

*these were at 18 inches and not 12
Click to expand...
That's huge. Good catch, my dear friend. Now if Ledil can work on that silicone finish! Or could we chuck up and entertain the idea of any dust acting as an agent for diffusion? :)
 
BOBBY_G

BOBBY_G

Well-Known Member
Greengenes707 said:
The end all test for this would be to put them in a sphere and see which is actually emitting the most total light. That is what I am curious, I have been looking for a sphere for lots of little test like such, no luck yet still.
Click to expand...
simple physics says that overall light is highest with no collimation or reflection
this would be followed by reflector (most light direct, some thru lossy reflectance)
at the bottom would be the lens (all light forced thru lens at 80-95% efficiency (at best))
 
robincnn

robincnn

Well-Known Member
organic-fanatic

organic-fanatic

Active Member
Greengenes707

Greengenes707

Well-Known Member
BOBBY_G said:
simple physics says that overall light is highest with no collimation or reflection
this would be followed by reflector (most light direct, some thru lossy reflectance)
at the bottom would be the lens (all light forced thru lens at 80-95% efficiency (at best))
Click to expand...
Yes. That what I have been saying for a long time now. Also the reason I prefer reflectors...in addition to their gains from a more diffused like light. They do have a fault, and that is physical protection. Which is a concern in my current world. But there is an official and scientific way to show total amount of light...a sphere. Until that is done, someone will always have an opinion.

The overall goals...
-The highest quality lens is the one that has the smallest ∆ between PPF with and without the lens.
-The most effective lens is the one that has the has the smallest ∆ between initial PPF and PPFD with a true flat plane integration technique.


Fixture efficiency- Measurements of fixture efficiency (lamp, luminaire, and ballast) were made by integrating sphere and flat-plane integration techniques. The integrating sphere measurements were made by a testing laboratory (TÜV SÜD America) that specializes in the measurement of the efficiency of lighting fixtures. Radiation measurements are calibrated to NIST reference standards. These measurements of fixture efficiency are considered repeatable to within 1 %.

Flat plane integration- Measurements were made in a dark room with flat black walls using a quantum sensor (LI-COR model LI-190, Lincoln, NE, USA), that was calibrated for each fixture with an NIST-traceable calibrated spectroradiometer. This calibration is necessary to correct for small spectral errors (± 3%) in the quantum sensor that occur because of imperfect matching of the ideal quantum response [16]. Measurements were made in three radial, straight lines below a level fixture and spatially integrated to determine total photon output. Measurements were made 2.5 cm apart near the center, increasing to 10 cm near the perimeter as PPF variation decreased. Fixtures were mounted 0.7 meters above the surface and measurements were made up to a 1.5 meter radius from the center and extrapolated farther using an exponential decay function. The flat-plane integration measurements were used to quantify the pattern of photon distribution from the fixture. Total fixture output from these measurements was similar to measurements made using an integrating sphere (Table 2). When redundant measurements were available, the integrating sphere measurements were used to quantify fixture efficiency.

***people please do not confuse this with the common "PAR map". FPI may be a map, but basic maps are not FPI.
 
robincnn

robincnn

Well-Known Member
BOBBY_G said:
simple physics says that overall light is highest with no collimation or reflection
this would be followed by reflector (most light direct, some thru lossy reflectance)
at the bottom would be the lens (all light forced thru lens at 80-95% efficiency (at best))
Click to expand...
I agree in a FPI or sphere test the COB with no optic would have most light. Reflectors and lens have their losses.


upload_2015-12-22_23-41-13.png
But in a grow room things are slightly more complex. Cobs have light coming even almost at 90 degrees to sides. All that light on sides would be lost if walls are not reflective. In bigger grow rooms you may not have side walls and actually open space to walk and again all that side light is wasted. Optics can help redirect this side light towards plants.
Even if sides are reflective, in a recent experiment i found the amount of light exiting from top of grow tent reduced when i put a reflector or lens.
I think this was because a lot of light emitted wide angles when hits the reflective sides get reflected up. A lens or reflector can tighten the beam enough so that more light reaches plants.
The slightly stronger light with optics may penetrate better. but then you an argue the diffused light reflected from sides increase penetration more. more Even coverage, LES protection, IP are other advantages of optics as well. but optics have $5-$11/COB price or even more .
I like the idea of using a suitable reflectors and lens, some may not.
I would love to know if anyone used 90 degree Angelina reflector or KB 80/120 lens and does not plan on using them anymore for next grow.
I did not say ledil stella or smaller 77mm 90 degree lens and other optics that may make the beam too tight.
 
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nogod_

nogod_

Well-Known Member
Why not use a projector-screen type partition (or just a projector screen they are designed to reflect light, no?) In the aisles and have it hung so its always angled down. It could even be hung near the fixture, pulled down over a guide and hooked to the table or floor.

exhibit A:





http://www.ebay.com/itm/119-Manual-Projector-Screen-84-X84-Pull-Down-Projection-Home-Movie-Theater-/310900765979?hash=item486321351b:g:zcEAAOSw5VFWGC1q



robincnn said:
I agree in a FPI or sphere test the COB with no optic would have most light. Reflectors and lens have their losses.


View attachment 3570350
But in a grow room things are slightly more complex. Cobs have light coming even almost at 90 degrees to sides. All that light on sides would be lost if walls are not reflective. In bigger grow rooms you may not have side walls and actually open space to walk and again all that side light is wasted. Optics can help redirect this side light towards plants.
Even if sides are reflective, in a recent experiment i found the amount of light exiting from top of grow tent reduced when i put a reflector or lens.
I think this was because a lot of light emitted wide angles when hits the reflective sides get reflected up. A lens or reflector can tighten the beam enough so that more light reaches plants.
The slightly stronger light with optics may penetrate better. but then you an argue the diffused light reflected from sides increase penetration more. more Even coverage, LES protection, IP are other advantages of optics as well. but optics have $5-$11/COB price or even more .
I like the idea of using a suitable reflectors and lens, some may not.
I would love to know if anyone used 90 degree Angelina reflector or KB 80/120 lens and does not plan on using them anymore for next grow.
I did not say ledil stella or smaller 77mm 90 degree lens and other optics that may make the beam too tight.
Click to expand...
 
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The Dawg

The Dawg

Well-Known Member
nogod_ said:
Why not use a projector-screen type partition (or just a projector screen they are designed to reflect light, no?) In the aisles and have it hung so its always angled down. It could even be hung near the fixture, pulled down over a guide and hooked to the table or floor.

exhibit A:





http://www.ebay.com/itm/119-Manual-Projector-Screen-84-X84-Pull-Down-Projection-Home-Movie-Theater-/310900765979?hash=item486321351b:g:zcEAAOSw5VFWGC1q
Click to expand...

Dude What's Up With your Ladies Giving Me The Finger :finger:
 
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