Alright, my last post about the E21A was more of a discussion into why the results sucked. The conclusion in the discussion seemed to suggest I needed to turn the power down to achieve perfection. So here is the official review, with a whole range of power levels (verified perfect by my Fluke), a fresh dark-calibration in the meter, and just a do-over in general for everyone’s sanity. Let’s see how this goes.
I am testing a:
Quad E21 “NVSWE21AT 5000K sm503-D240-M1-R9080” from Virence.com
For these tests I am not using any light modifiers, just a bare board as seen above. I hold the meter a measured 1-foot from the emitter, and at a slight 10-degree angle so I avoid the direct center of the emitter just a bit.
And the results are in:
—0.250A—
CCT: 5813
Duv: –0.0034
CRI: 95.9
R9: 82.9
TLCI: 98
—0.500A—
CCT: 5862
Duv: –0.0047
CRI: 95.3
R9: 82.9
TLCI: 98
—1.00A—
CCT: 6000
Duv: –0.0070
CRI: 94.2
R9: 80.5
TLCI: 97
—2.00A—
CCT: 6176
Duv: –0.0104
CRI: 92.8
R9: 75.8
TLCI: 96
—2.50A—
CCT: 6357
Duv: –0.0116
CRI: 92.5
R9: 74.0
TLCI: 96
So the CCT is horribly cold compared to the advertised 5000k. The Duv ranges from low to horribly low. And low Duv is not a rosy tint at this high of a CCT. It’s a blueish-purple tint, as seen below. The CRI (Ra) does hold spec across all tests. The R9 (the 80-minimum part of R9080) falls out of spec past 1 amp.
And this all makes sense with what I see, The meter is not wrong. Grass and plants appear cold and blue when lit by this light at night. The effect is mild when running 0.500 amp and extreme when running 2 amp.
So is this a fluke? Nope. I have two of these quads, and they are identical. It’s just the way they are when used bare. This is the true performance of the emitters.
Update: It turns out the advertised CCT and tint are rated at 700ma in a lab-grade integrating sphere, and that bare emitter performance is expected to be wildly different.
Adding a TIR lens to mine and turning the power down to 700ma was able to bring the CCT down to 5261. This is much closer to the advertised CCT, though still high. Unfortunately adding a TIR lens is not an option for my photo lighting needs. It simply doesn’t match my ambient light. This project is still a bust for me.
When I bought the ‘5000K’ I wrongly assumed that advertised output was mostly valid for any real world use. The Virence store makes no mention of needing to add optics to approach the advertised CCT.
Review Data:
E21A Review Data.zip