Luminus SST-20-W 4000 K CRI95 color and output test

217 posts / 0 new
Last post
maukka
maukka's picture
Offline
Last seen: 1 hour 10 min ago
Joined: 12/31/2015 - 04:15
Posts: 1962
Location: Finland

Sometimes it does, sometimes it doesn’t. Usually not any meaningful amount in either direction if the emitters are similar WRT CRI to begin with.

http://budgetlightforum.com/comment/1356557#comment-1356557

Jerommel
Jerommel's picture
Offline
Last seen: 5 months 2 weeks ago
Joined: 01/04/2014 - 13:18
Posts: 5721
Location: the Hague, Netherlands

what is WRT ?

2Q19

Agro
Agro's picture
Online
Last seen: 2 min 51 sec ago
Joined: 05/14/2017 - 11:16
Posts: 4781
Location: Ślōnsk

Maybe your spectrum has a lot of blue and a lot of red but a hole in the middle?

adam7027
Offline
Last seen: 16 hours 59 sec ago
Joined: 09/26/2017 - 13:54
Posts: 456
Location: EU (Hu)
led4power wrote:
But why CRI drops, it doesn’t make sense?

I think, it does make sense, since a spectrum, which exactly matches a black body radiation is considered as 100 CRI.

(For now, let’s assume, that a given spectrum is perfect for a given color temperature – we don’t want to mess with correlated color temperature /which is calculated for suboptimal light sources with uneven spectrum/)

Once the tint goes above or below black body line, it is not an accurate black body radiation anymore – so it cannot be 100 CRI in any circumstances.

The reason why many people tends to prefer ‘under BBL’ tints, that it gives more saturation to the scene.

Please correct me, if I know/remember it wrong, but the latest LED tests now work with two summarizing value instead of single CRI (Ra).

The first one is R-fidelity (Rf) – which would mean the accuracy of the color rendering – which can be max. 100.
The second one is R-gamut (Rg), which actually can be more than 100.

If above 100, we speak of adding saturation to the scene (this is when ‘under BBL’ tints), as we get more light for the parts of the spectrum, where human eye is less sensitive, thus color perception gets boosted somewhat (as a ‘side effect’, tint becomes rosy) – this effect can be regarded as pleasant and can be felt as a ‘superior’ light source – making the CRI/Rf drop seem to be of no sense, despite the measurements.

If under 100, we speak of desaturating the scene (when using ‘above BBL’ tints), where we tend to miss blue and red colors from the scene, and we talk about a tint being ‘greenish’ in most of the cases – these tints sometimes can be felt less useful/‘inferior’ even with relatively high CRI/Rf readings.

Look at any measurement, which is recently provided by maukka. You can see a graph on the right with Rf and Rg coordinates. You can see a triangular area, which has white background (or another with lighter gray) – this shows, that how much under/oversaturation (difference to 100 on the Rg axis) is possible for a given value on the Rf axis – of course, less under/oversaturation is tolerated, if one would go for a higher Rf value.

Now I hope, this makes sense to you Smile

This is why I love that red dot in that graph (and the 99 color samples as well, but for a different reason).

contactcr
Offline
Last seen: 3 hours 12 min ago
Joined: 05/19/2017 - 18:52
Posts: 2847
Location: US

Im going to try and mix 2x Luxeon MZ 3000K and 2× 5700K so i hope these results are similar. Someone should start a color mixing thread (maukka)

TBone
Offline
Last seen: 1 day 21 hours ago
Joined: 01/27/2016 - 16:42
Posts: 346
Location: Europe

Here is why the CRI drops when mixing different LED tints.

The 100% curves for the CRI are taken from the perfect black-body radiation at different (color) temperatures. Each curve has a different maximum point and slightly different shape. 5000 K has its maximum at 580 nm and 2700 K at 1070 nm.

(Discaimer: The CRI uses black-body curves only for a CCT below 5000 K. The ‘Illuminant D’ data used for higher CCTs are too ugly to show here.)

 


After standardizing the curves (divide all values by the maximum value, so maximum is always 1; easier to compare) and zooming into the area of visible light you get this:

For each wavelength your LED has to get near the curve to get a good calculated CRI value. (These curves are the blue ones in maukka’s diagrams.)

The curves look relatively similar to each other, just shifted left and right so each shows a different part of itself in the visible light range.

 


Now lets mix a high CRI 2700 K and a 5700 K LED.
Their spectra almost fit the 2700 K and the 5700 K curve. You mix their tints by summing up the values of the two curves for each wavelength. For the same power output on both LEDs that is the dashed line.

If you make one LED brighter and the other one dimmer the curve will only change slightly. Only the maximum and the slope will get closer to the curve of the stronger LED.
See the dotted 0.4/0.6 and the slash-dotted 0.8/0.2 curves for some mixtures. The slash-dotted line would not be too bad for 3500 K but with too much blue.
I could not mimic the shape and position of the 4200 K curve.

The more the mixed tint gets away from one LED tint the worse the mixture gets. Without a curve similar to the 100% CRI curve the calculated CRI value will be bad.
To really change the color temperature of an LED you would have to shift the wavelength, not just modify the amplitude.

The penalty in CRI will be lower with less distance between the tint of the LEDs.

Agro
Agro's picture
Online
Last seen: 2 min 51 sec ago
Joined: 05/14/2017 - 11:16
Posts: 4781
Location: Ślōnsk

Thanks TBone, great explanation!

djozz
djozz's picture
Online
Last seen: 6 min 13 sec ago
Joined: 09/07/2012 - 17:04
Posts: 15999
Location: Amsterdam

Nice post Tbone!

Barkuti
Barkuti's picture
Offline
Last seen: 2 hours 32 min ago
Joined: 02/19/2014 - 14:46
Posts: 4303
Location: Alhama de Murcia, Spain

0K, is this tint mixing sheesh serious? LoL! On top of this, now it seems like the way we perceive light is not that close, with people boasting more than 3 types of cone cells besides rods lmaohttps://en.wikipedia.org/wiki/Cone_cell

I have quads with high CRI 5500K + 4500K + 4000K + 3000K emitters, guess this should be working around right (without spoiling the CRI too much lol). Big Smile

 

Cheers Party 

staticx57
Offline
Last seen: 15 min 39 sec ago
Joined: 04/11/2016 - 00:43
Posts: 681
Location: New Jersey, United States

Also pretty interesting read on the topic of shifting tint: https://dammedia.osram.info/media/resource/hires/osram-dam-3813127/Brill...

Agro
Agro's picture
Online
Last seen: 2 min 51 sec ago
Joined: 05/14/2017 - 11:16
Posts: 4781
Location: Ślōnsk

staticx57 wrote:
Also pretty interesting read on the topic of shifting tint: https://dammedia.osram.info/media/resource/hires/osram-dam-3813127/Brill...

Interesting. I wonder if that’s why Zanflare T1 includes red LEDs?…and if this technique can benefit BLF lantern. Wink
contactcr
Offline
Last seen: 3 hours 12 min ago
Joined: 05/19/2017 - 18:52
Posts: 2847
Location: US

I think I might have messed up my first sst-20 build with this LED. Built an E2L triple w/ FET driver. 20 gauge wires to LED and spring bypass. Worked fine when i was testing using 10A Sanyo then i topped up a Samsung 25S which is the highest drain battery i have and now all modes noticably more yellow. I measured around 2,470lm at 0s just before this happened. On moon mode the emitters are still evenly lit but still yellow.

Not sure if bad reflow or over current.

Anyone else try DD triple with these?

Geuzzz
Geuzzz's picture
Offline
Last seen: 1 week 5 days ago
Joined: 10/25/2015 - 10:27
Posts: 1114
Location: Netherlands

contactcr wrote:
I think I might have messed up my first sst-20 build with this LED. Built an E2L triple w/ FET driver. 20 gauge wires to LED and spring bypass. Worked fine when i was testing using 10A Sanyo then i topped up a Samsung 25S which is the highest drain battery i have and now all modes noticably more yellow. I measured around 2,470lm at 0s just before this happened. On moon mode the emitters are still evenly lit but still yellow.

Not sure if bad reflow or over current.

Anyone else try DD triple with these?

Don’t have a triple, but just put one in a D25c with a fet driver. No yellow yet, it does have a tiny bit of green when comparing to other lights on a white wall.

contactcr
Offline
Last seen: 3 hours 12 min ago
Joined: 05/19/2017 - 18:52
Posts: 2847
Location: US

Djozz and maukka both had one die around 7A. Aren’t you worried or do you have higher resistance from bat or springs?

Edit: just noticed thats a 16340 host so that should be pretty safe

Geuzzz
Geuzzz's picture
Offline
Last seen: 1 week 5 days ago
Joined: 10/25/2015 - 10:27
Posts: 1114
Location: Netherlands

contactcr wrote:
Djozz and maukka both had one die around 7A. Aren’t you worried or do you have higher resistance from bat or springs?

Edit: just noticed thats a 16340 host so that should be pretty safe

16340 cell, no spring bypass, not to thick wires. Wont be doing 7 amps, probably max 5. But indeed not a light to lend out to muggles.

Geuzzz
Geuzzz's picture
Offline
Last seen: 1 week 5 days ago
Joined: 10/25/2015 - 10:27
Posts: 1114
Location: Netherlands

Played with it for a few hours last night. Pretty nice, like it better than the 219b sw40 that was in my light before the sst.

SKV89
Online
Last seen: 1 min 43 sec ago
Joined: 12/10/2017 - 12:46
Posts: 3188
Location: US

Why do you like it more than the 219b? Is it a 9080 or 9050?

Geuzzz
Geuzzz's picture
Offline
Last seen: 1 week 5 days ago
Joined: 10/25/2015 - 10:27
Posts: 1114
Location: Netherlands
SKV89 wrote:
Why do you like it more than the 219b? Is it a 9080 or 9050?

It was a 9080. I am strange I think… I find the sw40 a bit boring to be honest. And the second sw45 to cold/violet.

DB Custom
DB Custom's picture
Offline
Last seen: 1 day 16 hours ago
Joined: 01/13/2013 - 22:28
Posts: 20324
Location: Heart of Texas

Y’all are really doing great with all this tint mixing thang! Smile

I’ve been looking at doing some mixing in a light I’m building that will have 17 emitters. 4 quads under Ledil Angie optics and a central single die under a 22mm reflector. I’m planning to use a sliced and sealed SST-40 in the center, originally planned 16 Samsung LH351D at 80 CRI 5000K for the quads. But I’ve been considering doing some mixing on these 4 quad boards. I have a lot of emitters to choose from, can even do a quad with 4 Black Flats and one with 4 Nichia 219C at 5000K, then maybe XP-L HD or HI or a mix of both. But I have so many options I don’t know what to do… could y’all help me figure this out?

Here’s a list of emitters I have available, the majority new and in tape, a few on boards as indicated…

The layout is like this, with the center (marked as HI) probably not being an HI but I’m still open to options.

So, would there be a viable combination in this slew of bare emitters or is it time to order something new?

This is a 4” diameter head mated to a Sofirn Q8. The center 25mm Maxtoch MCPCB is run from the original driver flashed with Anduril, there are 4 slave boards each with an FET+1 set-up that will run the 4 quad Noctigons (D4S, with Angie optics) So each quad can have different emitters, Vf differences won’t matter as the board will have it’s own FET+1 supply, with all 5 drivers being controlled by the same Anduril UI. I started out wanting max lumens, but after all the work this has been I’m thinking I should just make it the best beam profile/tint I can put together.

Any and all help here is greatly appreciated. Smile Y’all are obviously the masterminds of mixing. Big Smile

Light is essentially ready to assemble, D4S boards and optics will be here Tuesday.

ToyKeeper
ToyKeeper's picture
Offline
Last seen: 7 hours 41 min ago
Joined: 01/12/2013 - 14:40
Posts: 10000
Location: (469219) 2016 HO3
DB Custom wrote:
Any and all help here is greatly appreciated. Smile

I hope it will work out well. I just haven’t tried mixing different types of emitters in parallel like that, so I’m not sure what to expect. It might end up driving the highest-Vf emitters extra hard while not doing much to the lowest-Vf emitters, or it might be fine.

As for getting the colors blended well, that’s going to be a pretty complicated equation. It might be easier to just try it and then make adjustments as necessary.

DB Custom
DB Custom's picture
Offline
Last seen: 1 day 16 hours ago
Joined: 01/13/2013 - 22:28
Posts: 20324
Location: Heart of Texas

Ah, well, the thing is… each board will have it’s own MOSFET and 7135 chip, so the different emitters won’t be sharing the same “parallel” board. Samsung emitters on a board will have their own FET and 7135 chip, if I put Nichia 219C’s on another board it will have it’s own FET and 7135 chip… there are 4 slaves and the original driver is the Master, each FET+1 will drive it’s own MCPCB full of emitters. Only the MCU will be shared. Basically 5 lights with 5 drivers housed in one unit. Wink With this configuration, I could feasibly put a sense resistor on one slave board and limit output to the emitters it supplies. I have 22ga leads coming from the original Q8 driver for example, to supply the Luminus SST-40. I don’t want it to try to pull 9A. This has no effect on the 4 slave boards which each have an 18ga Teflon coated negative lead to it’s respective board.

I will be sharing the red positive lead between two quad MCPCB’s, 2 leads for 4 quad MCPCB’s, this is a huge 14ga lead and will carry whatever current the power pack has to offer. I could, in theory, add a 6th slave with a single 7135 for each channel and run green XP-E2 emitters at a maximum output of 350mA, powered from the same power supply but unaffected by what it’s neighboring MCPCB’s are doing. I thought about doing this to run a string of green emitters around the perimeter to add a glow behind the mains… decided not to. In much the same way that I could run a rainbow of small SMD emitters around the perimeter and engage them through the switch light leads, again, not going to as it’s already complex enough. lol I have all these emitters, 8 colors of SMD’s, so tempting to use them…

Edit: Hank is offering 4 emitter choices for his D4S, I can use essentially those 4 emitters on 4 boards under 4 optics and add the center SST-40 under a 22mm reflector, which, in theory, would be good for some 17,700 lumens (expecting ~ 2000 from the SST-40)

From Hank’s site, regarding the D4S…

OTF lumen output and candela at start-up

XP-G2 S4 : 3300lm / 40,000cd

Nichia 219C : 3000lm / 20,000cd

XP-L HI : 4300lm / 45,000cd

XP-L HD : 5100lm / 27,000cd (I can either use XP-L HD or Samsung LH351D)

It just intrigues me what the beam would be like with all 4 D4S emitter choices coming from one light. Think I gotta do this… lol

contactcr
Offline
Last seen: 3 hours 12 min ago
Joined: 05/19/2017 - 18:52
Posts: 2847
Location: US

I shaved the dome on my SST-20 4000K E2L triple. It does appear to have made it slightly less green at the expense of not very much loss of CCT. I expected more anyways. I think it’s throwy enough with the dome on though so I wish a different tint existed but you get what you get Smile

Here is a comparison, both have smooth narrow optic using lightly used 30Q/VTC6

SST20 4000K (SD)
14.2kcd
1750lm

and for reference:

XP-L HI V2 5D
14.7kcd
2230lm

EasyB
Offline
Last seen: 34 min 32 sec ago
Joined: 03/09/2016 - 15:24
Posts: 1706
Location: Ohio
DB Custom wrote:
It just intrigues me what the beam would be like with all 4 D4S emitter choices coming from one light. Think I gotta do this… lol

I think the beam will look good. Those four emitters are not that different in size so I don’t think the beam will look at all strange. The largest (XPL HD) is only ~1.5x larger in diameter than the others. In my 7xC8 light I used different emitters (sliced SST40 and sliced XHP70.2) and the beam looks good.

Barkuti
Barkuti's picture
Offline
Last seen: 2 hours 32 min ago
Joined: 02/19/2014 - 14:46
Posts: 4303
Location: Alhama de Murcia, Spain

De extremized my quads to 2x 4000K and 2x 4500K after this TBone's contribution.

On the other hand since available emitters tend to be above the black body locus, any of you believe mixing close tints could actually “enhance” the resulting tint mixture's BBL position? Let's say, mixing a 3000K high CRI emitter (Samsung LH351B 3000K CRI90+) with another 4000K high CRI emitter (Luminus SST-20 4000K CRI95+).

With regards to CRI it shouldn't be very detrimental, what do you think? 

 

Cheers Smile 

Thu, 11/15/2018 - 03:10

twisted raven
Offline
Last seen: 2 hours 15 min ago
Joined: 03/13/2016 - 11:10
Posts: 476
Location: texas

Just put a minus green filter over it to better your tint and cri.

Pavlo
Offline
Last seen: 28 min 41 sec ago
Joined: 12/13/2015 - 10:37
Posts: 513
Location: Canada

CCT aside, what are the Pro’s and Con’s of this SST20 LED vs the older 219b 9080?

My understanding so far… did I miss anything?

219b:
+Best tint and closest to BBL
-Cannot be driven very hard in a direct drive light.
-Very slightly less bright/efficient than SST20

SST20:
+smaller die = better throw/intensity
+very slightly more bright/efficient over 219b 9080
+can handle higher current in direct drive lights
-Tint is above BBL

Which one do you prefer and why?

SKV89
Online
Last seen: 1 min 43 sec ago
Joined: 12/10/2017 - 12:46
Posts: 3188
Location: US
twisted raven wrote:
Just put a minus green filter over it to better your tint and cri.

The problem is you lose 17% to 20% output with the Lee Filter, which means the SST-20 will output a bit less than the 219B 9080. So in that case, might as well just get the 219B 9080.

Pavlo
Offline
Last seen: 28 min 41 sec ago
Joined: 12/13/2015 - 10:37
Posts: 513
Location: Canada

Can anybody explain or know how a multi emitter SST-20 light will perform in a constant current Boost driver vs a 219C that has a lower Vf?

ImA4Wheelr
Offline
Last seen: 1 day 23 hours ago
Joined: 02/03/2013 - 14:51
Posts: 7916
Location: SC

SKV89 wrote:
twisted raven wrote:
Just put a minus green filter over it to better your tint and cri.
The problem is you lose 17% to 20% output with the Lee Filter, which means the SST-20 will output a bit less than the 219B 9080. So in that case, might as well just get the 219B 9080.

 

Is that loss across the emitter's spectrum or just in the targeted color range?

wstrachan
Offline
Last seen: 20 hours 6 min ago
Joined: 02/19/2016 - 02:30
Posts: 633

High CRI and minuscule tint shift is great but it seems to take high current numbers to reach just a hare under 1100 lumens. 6.7A at near 4 volts (26W+). I don’t really see the purpose over other emitters (Nichia, XML’s, XPG).

light addict....yeah I've got the bug.

Atrolux MF02_O2S
Imalent DT70
Emissar (All Models)
Lumintop ODL20C
Wuben A21 & T70
thrunite tn32 ut
acebeam k60
many, many others...

Pages