Zebralight SC64c (XP-L2) measurements or "why 2-step means squat"

I tested some non Easywhite binned 4000K XP-L2s a while back and found the CRI90 versions to be green/yellow in tint while the CRI70 versions were quite alright. Both suffered from the tint shift within the beam i.e. the Cree rainbow.

The 2-step CRI90 XP-L2 in the Zebralight SC64c should guarantee a nice tint, but several reports from users have indicated otherwise. Fortunately a fellow flashlight enthusiast loaned me his SC64c for testing. He has already decided to return it as he was spoiled by the much nicer H600Fc.

Beam and tint

Turns out that the 2-step means squat. The light doesn't measure inside the 2-step quadrangle at any point in the beam. So obviously it doesn't do it integrated either. For this single reason, I would return the light. The 2-step offered by Cree is not a reason for Zebralight to not use Nichia and I've never seen anything this bad from a 219C or 319C even though they can't match the luminous efficacy of the XP-L2.

There's an almost indistinguishable brownish spot in the middle of the hotspot. The corona is a strong yellow/green and the spill again turns cooler. Yellow is probably the best shade to describe the overall tint. Definitely not the prettiest of beams.

Tint within the beam



Tint in different brightness modes



Beam profile





The color temperature stays warm all the way to the edge of the spill. Fortunately there's no strong purple there.





The duv (deviation from the neutral black body line) stays on the greener side of things throughout the beam peaking in the corona.

Color rendering

The CRI(Ra) is some 2-5 points under the advertised 93-95, but that wouldn't be a deal breaker for me at least. Color rendering drops on the higher modes which is common for single die high CRI Crees.





CRI data on H2

CRI data on M1


Output and runtimes

The Zebralight SC64c was tested with the battery they recommend, a Sanyo NCR18650GA. Button tops or protected cells don't fit in the light.





The PID thermal requlation hunts a bit in room temperature on H1. If cooled well enough, the light doesn't step down.



The output falls a bit short of advertised (814 vs. 900 lumens or -10%). On H2 or "341 lm" the difference is bigger as I measured it at 283 lumens (-17%). This discrepancy is strange as usually their numbers are accurate, though some of the difference can be explained by the sample variance. ZL doesn't have runtimes listed on their site at the time of writing this.

Zebralight does deserve the usual praise for their amazing driver which offers rock solid output regulation and excellent efficacy. Assuming the emitter used is the XPLBWT-00-0000-000UU640H which is spec'd at 417lm @ 1050mA / 2.90V or ~3W it has an efficacy of approximately 140 lm/W.

The losses from the driver, reflector and lens are very small. I got 117 lm/W on the H2 mode. This is the highest I've ever tested for a CRI90 flashlight. 80 lumens for over 21 hours is also quite a feat.

Just give the ultimate EDC light to us with a decent emitter, please.

Flicker

There's some ripple on L1, but because of the limited modulation depth and high frequency it isn't visible. On higher modes the flicker is non existent.



Flicker on H1
Flicker on H2
Flicker on M1

Standby drain

There's insignificant parasitic drain on the battery when the light is switched off. I measured the standby drain at a minimal 26µA.

Thanks for another great review maukka👍.

I will say that it sounds like I definitely won the tint lottery compared to your sample. While mine still obviously doesn't have the greatest tint or tint consistency across the beam(being a Cree with the new full phosphor coating), it has no brown spot and the hotspot is slightly rosy on the higher levels. It is still quite yellow for the most part however(particularly in the corona). Personally, the tint has grown on me and without comparing it to other rosier light sources, it is quite nice to use at night imo.

I do also wish ZL would switch to Nichia however. Or at least offer some models with Nichia emitters. Although, it should be noted, had they had gone with a 219C in this model the output and efficiency would not have been near as good. So, it is a tradeoff.

I should also point out that 2-step emitters are not meant to offer a "guaranteed nice tint" but, only better tint consistency between samples compared to the lower stepped bins.

Unfortunately the particular bin ZL chose for this model falls mainly above the BBL. So, maybe they should have went with a lower stepped bin to allow more samples to be on or under the BBL but, that would have meant more extreme samples too(both very yellow/green and very pink/magenta) so again, it is a tradeoff.

Thanks for the helpful review Maukka! I bought the SC5C Mk II XPL2 4000k 93-95CRI and returned it immediately because of how greenish the tint was. I'm asking Zebralight to exchange for a SC5w MKII XPL2 4500k 80+CRI hoping the tint will be more rosy in color. I was planning to buy a few of their new XHP50.2 flashlights and headlamps but I'm afraid of the tint lottery. Do you think the XHP50.2 4000k 93-95 CRI have the same chances of getting greenish tint compared to the XPL2? If so, I don't think I will risk it. So sad as I really wanted to buy Zebralights since they are known for their premium quality.

Awesome review, thank you.
Will avoid this one for white wall hunting haha!

Excellent review!

I'd like to see a review from you for the sc600w HI IV

Wish we had some H600Fc/d to see as well.

It's a shame the MT-G2 has fallen out of favor for shinier newer emitters. Its beam consistency is fantastic but back when it was all the rage there were no drivers to drive it from a single cell. Bad timing and all with the recent proliferation of drivers which can do 6V or 12V from a single cell.

I've been both looking forward to and dreading the day when Maukka tests one of the newest high CRI Zebralights, because I've suspected results would be something like this. Armytek needs to take a look at this and realize what a standout product they would have if they follow through on the Nichia Wizard.

I assume a 2-step bin means all emitters in the same bin have an average output across the beam within 2-steps of each other, and probably look a lot more even either as a mule or seen through a diffuser. I wonder if the averaging that occurs if you diffuse the beam would bring the total result closer to where it is supposed to be, but looking at your duv vs. beam angle graph, it's got to be borderline at best.

Is that quadrangle you plotted based on the cornerpoints called out in the datasheet for the Easywhites?

I also wonder whether this could be a matter of bad binning on Cree's part, or Zebralight not actually using 2-step Easywhites as they claim.

At least the efficacy is really, really good, and the R9 score looks decent.

I posted in another thread about returning my SC64c due to green tint. I figured the specs were off from what was listed. I measured the color temperature of mine to be closer to 4500k and thought my H600fc mk III had better color rendering. IMO the cri rating means nothing if the tint is bad. I would have paid extra for guaranteed tint.

iamlucky13 said:

Is that quadrangle you plotted based on the cornerpoints called out in the datasheet for the Easywhites?

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Yes, page 16 on the XP-L2 datasheet. The hotspot doesn't even fit the 5-step ellipse. Integrated it's also far off from the promised 2-step.

I wonder if it's Cree that's not delivering to their specs as opposed to Zebralight. Either way, very unfortunate that it's so off spec for a 2 step... I assume the h53c mimic these results.

I don't see it being Zebralight's fault, as they're ordering bulks of a certain spec'd LED under the assumption that it should be that very spec. 3 and 5 step variants don't come with 90 cri.

Sounds like Zebralight needs to ***** at Cree.

Re: Zebralight SC64c (XP-L2) measurements or &a mp;a mp;a mp;a mp;a mp;q uot; w hy 2-step means squat& amp; amp; amp; amp; amp; amp; quot ;

I would like to see more samples tested to see if this is just a bad sample.

Re: Zebralight SC64c (XP-L2) measurements or "why 2-step means squat&amp

Thanks a lot maukka, awesome as always.Looks like Cree is sending out lemons to buyers who pay a hefty premium and hopes to get away with it. Fortunately while the XP-L2 on my H53Fc still produces a coppery - yellowish corona, the tint of its spill is almost identical to that of my 4000K D4vn, less the typical Nichia pinkness. I'll see how my H600Fc MKIV does in the tint arena... DHL handed the parcel to Auspost and for some reason stupid Auspost has been holding it for an entire week.. I feel silly carrying a fully charged 18650GA to work for the week hoping that the light would show up at the local post shop:mecry:

twistedraven said:

I don't see it being Zebralight's fault, as they're ordering bulks of a certain spec'd LED under the assumption that it should be that very spec. 3 and 5 step variants don't come with 90 cri.

Sounds like Zebralight needs to ***** at Cree.

Click to expand...

If you are selling things with tight specifications you need to test them, they either knew they were way off or they have zero quality control. Considering someone got one with the wrong model engraved on it, I'd bet on the later.

1000cri said:

If you are selling things with tight specifications you need to test them, they either knew they were way off or they have zero quality control. Considering someone got one with the wrong model engraved on it, I'd bet on the later.

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No matter how good a company is at QC there will always be a few lemons that slip through the cracks, it happens to every company. Zebralight definitely isn't perfect and the lights are still a bit of a tint lottery but they're much improved from what they used to be.

Maukka, thanks for sharing these measurements. I've been contemplating replacing my SC63c and I'm still thinking about doing so. I personally like the golden yellow tint my SC5 MK2 has and would love to get a 64c with that... but green is definitely not something I can put up with.

Maukka, thanks for the time spent on a great review. Fwiw, my sample is very consistent color across the beam, and turns a white wall a bit yellow, so it seems that I might have one of the better samples.

For those questioning the ZL "quality control", they are obviously suggesting that ZL should be doing a 100% inspection of beam color on every LED. I don't want to pay those kinds of prices. Cree process control and QC, on the other hand, is obviously lagging behind their marketing department.

Keitho said:

Maukka, thanks for the time spent on a great review. Fwiw, my sample is very consistent color across the beam, and turns a white wall a bit yellow, so it seems that I might have one of the better samples.

For those questioning the ZL "quality control", they are obviously suggesting that ZL should be doing a 100% inspection of beam color on every LED. I don't want to pay those kinds of prices. Cree process control and QC, on the other hand, is obviously lagging behind their marketing department.

Click to expand...

I wish they had a tint snob version, with either a hand picked Cree, or a Nichia. I would pay extra for that.

1000cri said:

I wish they had a tint snob version, with either a hand picked Cree, or a Nichia. I would pay extra for that.

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Same for me.

I have three of these Zebralights (SC64c, SC5c II, SC53c) with 90+ CRI 2-step XP-L2 emitters and while yes, there is a yellowish corona on all of them, it's only really visible at close range on a white wall. In use it's not a problem. All three are also extremely close in tint and CCT, such that even white wall hunting I'd have extreme difficulty in guessing which is which.

While the numbers may not look great, in terms of real-world usage I don't think there's much to complain about here.