Nichia vs Luminus SST-20 high CRI

[JoakimFlorence]

This is a comparison between two widely used high CRI emitters for flashlights.

Some of you may be familiar with the name "Nichia 219a". Technically that designation has been discontinued and modern product is now 219CT.

If you are looking for a high CRI emitter, you may be wondering which one to use.

Note that not all SST-20 emitters are high CRI, but rather they make different versions with different CRI levels, and the same is true for Nichia's 219CT. So we'll be looking at the highest CRI versions.

Luminus SST-20-WxH 95CRI
J5 flux code bin (in the middle) 210 lumen flux at 700 mA

Nichia
NVSW219CT (R9050 92 CRI version)
254 lumen flux at 700 mA

You'll notice that we are comparing a 92 CRI LED to a 95 CRI LED. There is going to be an inherent trade-off in lumen efficiency (amount of visible light).

Note that the 92 CRI Nichia puts out 20-21% more lumen output than the 95 CRI SST-20.

The SST-20-WG, on the other hand is 90 CRI.
D1 flux code bin (in the middle) is 360 lumens at 1000 mA, compared to 284 lumens at 1000 mA for the SST-20-WxH 95CRI (J5 flux bin).
So we see that the 90 CRI puts out 26-27% more lumens than the 95 CRI version.


Now for some explanation on exactly what these different CRI levels are actually like.

90 CRI is noticeably a notch better than average LED lighting (and certainly so much more colorful than 70 CRI flashlight LEDs), but still you can tell some of the color is sucked out. Things could look more vibrant and colorful.

92 to 93 CRI is when warm wood tones and skin tones start to look fully warm and lively. The downside is sometimes pure red colors can appear like less of a pure red and appear just a little orange-toned.
In my personal opinion, for those who nitpick about light quality, 93 CRI is when things truly get to the level of "satisfactory" and nice for an indoor living space. You can start to feel the light has some "warmth" (this separate from the concept of color temperature).

95 CRI is fantastic color rendering. Red colors will really pop and colors that are supposed to be warm will truly appear fully warm. You'll get maximum color contrast between red and green colors and things will look very lively. Often starting at 95 CRI the LED light will begin taking on more of the feel of other natural light sources.
At this point we're talking about light suitable for displaying paintings for artistic purposes.

There is no reason to really need higher than 90 CRI for a flashlight, but the light will just be nicer in appearance and things will seem more pleasant, more colorful and lively. For many people who are less sensitive, they may not even perceive any improvement after the CRI goes above 90.

For a flashlight, I personally think the Nichia (at 92 CRI) is a good compromise for those desiring higher CRI.

 

[JoakimFlorence]

According to the specs, Nichia 519AT-V1 , in the R9080 (93 CRI) version, has a lumen flux of 390 at 1050 mA. (Which we can roughly estimate would be equivalent to 371.4 lumens at 1000 mA)

So this seems to be better than the SST-20 in terms of lumen output.

 

[JoakimFlorence]

According to information I was able to find, the SST20 comes in 5 different CRI options

SST-20-WxS ... >65 70 typical CRI
SST-20-WE ... >70 CRI
SST-20-WF ... >80 CRI
SST-20-WG ... >90 CRI
SST-20-WxH ... >95 CRI

I sent an email contacting the official Convoy flashlight site asking what version of the SST-20 they used in their flashlights, and received this reply:

SST20 6500K 5000K , r70
SST20 4000K 3000K , r95

So supposedly the 3000K and 4000K SST20 LEDs they are using are 95 CRI, while the 5000K and 6500K ones they use are 70 CRI.

 

[JoakimFlorence]

Here's a look at how choice of color temperature can have some impact on lumen efficiency. Especially at higher CRI levels.

SST-20-WH30-B2-B5302 ... 95 CRI ... 3000K ... 121 lumens
SST-20-WH35-A2-B6351 ... 95 CRI ... 3500K ... 128 lumens
SST-20-WH40-B2-B7401 ... 95 CRI ... 4000K ... 135 lumens

As you can see, at this high CRI level, the 3500K has a 5% lower lumen rating than the 4000K.


SST-20-WG40-A2-C8402 ... 90 CRI ... 4000K ... 238 lumens
SST-20-WG50-A2-C9502 ... 90 CRI ... 5000K ... 250 lumens

At 90 CRI, the 4000K has about a 5% lower lumen rating than the 5000K.


(It should be noted that this lumen output is for when the emitters were driven at 700 mA, and is only for comparison. The SST-20 family of emitters have a maximum rated current of 2000 mA)

 

[aznsx]

Thanks for the info you've posted in this thread. I, for one, find it to be of interest and potentially useful. My knowledge of the subject matter is limited, so I have a lot to learn, and appreciate any such info. Thanks again!

 

[JoakimFlorence]

The SST-20 - 95 CRI, in 4000K - has a light quality that comes very close to approaching the feel of natural sunlight. Green leaves and red things have an excellent color appearance under it. You couldn't ask for better light quality for a flashlight.
However, I'm beginning to see why this emitter might not be so practical for a flashlight. The amount of light output is definitely less than the Nichia 519A - 93 CRI.
With the Convoy flashlight frame, to really have plenty of light, you have to set in on the highest setting, whereas using the 519A, the second highest setting provides plenty of light. And running the flashlight on the highest setting, you're going to drain the battery faster, and when continuously left on, the flashlight gets very warm in not too long of a time. (In other words, you're probably not going to want to just leave it on the highest setting and just forget about it)

Now, the 519A - 93 CRI provides good light quality - great for a flashlight. But it still feels a little bit half like "LED light". A disclaimer, I'm probably a very picky person when it comes to CRI, but the color appearance of things under this light could be a little better. This is, I think, especially true at lower light levels were the eye has more difficulty seeing color.
Let me clarify, 93 CRI is definitely "good enough", for anything, but it is definitely noticeable to me that the colors could look better. You'll get a "good" color contrast between red and green colors with the 519A, but it may not quite be "art display" quality, and will fall just a little short of absolute full color vibrancy.
The 519A does have great light color tint though (color appearance of the light itself).

The light quality from the 519A still will be noticeably better than the B35AM (square) emitter, which is 90 to 92 CRI, and is also considered "high CRI". I mean in terms of the light feeling like it has "warmth and fullness".
Some might like the B35AM because it is a bigger square emitter, and can handle more power, as well as has a little more of a spatially distributed direction of light output (if you want to light up a wider close area rather than have a tighter beam).

The 519A in 3500K in a flashlight almost feels like it could be incandescent light (in terms of color appearance). It has a quality that still makes it look a little "dull" and "orangish", but still has a little "brightness" and more LED white color like than a real incandescent flashlight.


I'll go back to the discussion about CRI and the 519A. Under normal circumstances indoors, it's virtually impossible to tell that the 519A is lacking in any color rendering ability. Everything will seem plenty colorful. (Maybe just the tiniest notch less than it could be in a very subtle way, but you would have to have an artist's eye to be able to notice that) However, outside in the dark expanse at night, it will be a little bit of a different story. When shining the light further away at fir trees or bushes in the winter, the color of the leaves will look just a very small bit dull and bluish in hue. It's still "good" color rendering but it's not as good as it could be. You might not really have the full vibrancy of color if the light is very spread out at lower light levels. This may especially be the case in winter where the green foliage on plants isn't as vibrant as it looks during other times of the year.
The 519A gives browns and fallen leaf colors much more warmth and color than other LED flashlights, but still the SST-20 - 95 CRI is going to be a little noticeably better. Solid red colors (at more of a distance, with lower light intensity levels) show up good under the 519A but could be a little better.
The 519A will be more than good enough for the vast majority of people, but for those who obsess over colors and need the absolute full vibrancy of color, the 95 CRI emitter can provide a somewhat better appearance.