Well crap!! Last night I placed an order for a NS14R and a A54U v2 both with batteries. 
BLACKFRIDAY code does not work for A10.
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Important note: the current Nealsgadget website is bugged for the A54 Ultra 2.
If you want to order the light in 4000k 95CRI you need to drop down to these options.
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I asked on chat about discount code for A10 but Neal said no go. Disappointed I then asked about 35% code for Nightwatch LW55, a second light that Iāve been tracking. Next thing I know he gave a 40% off code ND40F and gave me the ok to post.
Just a brief summary of this light based on youtube review by flashaholic: 8000lm, 800m throw, looks like very nice run-time with regulated driver, white beam without tint shift. 29 buck - absolutely nothing comes close at this price.
Why I want it? This is a less throwy, more floody version of my SBT90.2 Wurkkos (typically 1100m throw, ~4700lm). Reviewer said āperhaps ever so slightly rosy hueā so the beam color should be more pleasant than the green tint of SBT90.2. Unlike A54U, I feel better about recommending this to people new to the hobby. Very likely an excellent 800m thrower with great brightness and great spill, although fast step-down is expected.
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25% and 30% codes work for A10 so you can buy it if you want. Only AK24 is on BlackFriday with 35% OFF but its totally not worth it looking at first reviews.
With Sofirn HS21 the Spot gets pinkier and the flood gets greener as the outputs increase.
SFT40? Iāve owned multiple samples of it and never observed such a phenomenonāthe spot and flood always change tint in the same direction. Do you have beam photos to help us see whatās going on?
Take a look at duv at Sofirn HS21 Headlamp Review - ZeroAir Reviews
It matches what I see.
Could you pls PM this 30% code to me? I tried ND30F and BLACKFRIDAY30 but neither works. Best I could get is 1LUMENNEW @ 25% off. Thanks.
I see. It should clarified that the spot and flood are separate channels with different kinds of LEDs. Although interesting, it should not be surprising that the different LEDs exhibit tint shift in different directions as current increases.
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BLACKFRIDAY doesnāt work on the A10. What code did you use to make it work?
Nightwatch A10 is out of stock per Neal. Brand is probably becoming more popular because of the unusually high performance/cost ratio and tank-like built.
BTW, if you want a Nightwatch, between now and Xmas is the best time to get them because of the significant 30-40% discount. Iād recommend to make sure light is in stock to prevent frustration. He answers my questions on the website chat.
I hope everyone has gotten good BLACKFRIDAY deals, butā¦ back to regular programming :).
Previously Iāve noted that unlike LED like Nichia 519a, the Duv of this N5-165 4000k LED becomes more positive as brightness increases. The change in tint especially noteable from level 3 to level 4. If you go through the levels while white-walling, itās quite easy to see this interesting change.
Pics to come later - hope it will show the change clearly.
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During white walling, I noticed a change in tint, most obvious from level 3 to level 4.
Measurements and this picture confirm what I saw. As brightness increases, Duv becomes more positive, and CCT increases, approaching 4000k.
(I used the Web App for LM3 to make my life easier. It unfortunately only shows Duv values to third decimal place. I added a 0 because 3 figure Duvās look so weird :).)
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I like the light at turbo better. But I tend to go for 5K over lower CCT lights. Just personal preference. I wouldnāt call it āgreenā. More a cream color with less red than the lower level. Anyway, it is interesting to see the difference 280K and 0.0030 DUV makes in the apparent beam color.
Has anyone seen a graphic that shows the effect of changing DUV while maintaining a constant CCT.
I have looked but couldnāt find anything.
I will have to try this with mine and see if it does the same thing. Thanks for documenting your discovery!
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Very nice beamshots! The increase in green is quite noticeable, I havenāt seen anything this severe.
I would avoid doing this, for sake of clarity, because 0.0020 is generally taken to mean āaccurate to 4 figures up to roundingā, but in reality you only have accuracy to 3 figures.
In theory, you could follow an isotherm on this chart and get RGB value readings or magnify a neighborhood of the point. But I find that screens are horribly inadequate at displaying shades of white in a way that is recognizable as white, and the chart may not have enough resolution for small changes in chromaticity coordinates. Plus, different monitors may display different colors even with the same RGB triple.
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I assume that stems from the switch of CC buck to PWM FET mode. In the latter, the LED is pulsed with full power (voltage), possibly leading to the same saturation effects of the phosphor, as others pointed out for Turbo.
One would thus expect each subset of steps 1,2,3 and 4,Turbo to have similar tints.
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You hit the nail on the head - very impressive considering you donāt own the light 
. I was fascinated when I found the Duv gives a clue to what the driver is doing āunderneath.ā (Discussed the same phenomenon in my comparison of the SFT-25R mini-throwers, Convoy Buck T8 against Wurkkos FET with PWM - will repost here next.) Here are my PWM measurements next to Duv in case they help to make your great explanation clearer to readers:
Level 1 = 130 lm, 3720k, Duv 0.002 no PWM-regulated/?Buck
Level 2 = 530 lm, 3740k, Duv 0.002 no PWM-regulated/?Buck
Level 3 = 1150 lm, 3764k, Duv 0.003 no PWM-regulated/?Buck
Level 4 = 3290 lm, 3961k, Duv 0.005 FET + PWM
Turbo = 14780 lm, 4000k, Duv 0.005 FET, no PWM
My observation: 1 to 3 is similar enough, then a sudden increase of green tint at level 4 and 5. (My possibly questionable subjective observation was confirmed by photography.)
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Iām sure there are swings in other LEDs too (SFT-25Rās Duv swings by 70 points between level 1 and Turbo). We havenāt seen these pictures more often probably because no one is crazy enough to do these painfully time-consuming A/B comparisons.
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I donāt know about this N5-165 LED but for Nichia, change of CCT and Duv versus current (and temperature) is documented. Below is the current chart for 519a.
If I read it right, looks like as forward current is increased, the x,y coordinates move leftward (higher CCT on the chromaciticy chart) and downward (more negative Duv)? I should check this some time.
