Convoy S21D w/ legendary Nichia 219b. Review & comparison w/ Nichia 519a, B35AM, FFL351A Rosy & "tint-snob" LEDs. (Summary & measurements on P. 1) LATEST: Firefly E07X with VERY rosy 351A LED and Lume1 Driver.👍

[cannga]

@cannga

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These are numbers from S21D with Nichia 219b 4500k. Brightness set at 10%. The light is on tripod as usual and in this setup I could see x,y coordinates drifting slowly 1 or 2 points at a time (4th significant figure).

Start: Duv –0.0084 CCT 4455
5 min: Duv –0.0088 CCT 4466
10 min: Duv –0.0091 CCT 4470
15 min: Duv –0.0093 CCT 4471
20 min: Duv –0.0094 CCT 4473
25 min: Duv –0.0095 CCT 4475
30 min: Duv –0.0096 CCT 4478

So Duv dropped about 12 points while the LED is heating up, and was still drifting slowly when I got bore and terminated test. I’ve seen the same thing with my 519a LED. (EDIT @ 25 min)

From AR lens Duv comparison to Duv drop with time and heat, the last couple pages of this thread contain the most fun and relevant discussion for me, all thanks to the humble Opple. And the tests are easy: the main thing is to NOT move the light or sensor once you’ve set them on stable platform. I repeated test, but with Nichia 519a 4500k, 10 degree clear lens, brightness 20%. Sensor 12 inches from light.

Start: Duv –0.0008 CCT 3876
5 min: Duv –0.0017 CCT 3849
10 min: Duv –0.0020 CCT 3840
15 min: Duv –0.0022 CCT 3834
20 min: Duv –0.0025 CCT 3825
25 min: Duv –0.0026 CCT 3822
30 min: Duv –0.0027 CCT 3818

A few things I noticed:

1. The Duv drops ~20 points after 30 minutes, even more than with 219b. Now I know, if I do the “wave test” (waving the light on the Opple) I will get a more positive Duv.
2. As LED heats up, CCT of 519a goes down, in opposite direction to 219b.
3. I previously wrote that the beam of 519a 4500k has a golden tone here, now I know why it does. The actual CCT of my 519a 4500k is ~3800k (plan to re-test with 60 Degree Bead lens). This LED should really be compared to 219b 3500k, not 4500k.