I call it the CATSS, “Cree AngularTint Shift Syndrome”.
It seems like a problem that is very miss-understood, but we all seen it from Cree LED emitters for years, and Cree still don’t seem to understand how to fix it in the way that Nichia & Luxeon has mastered the phosphor coating & design to make it right.
Incandescent lights don’t have it, fluorescent don’t have it, HID don’t have it, but LED technology still suffers from the limitations of how the dies work as a flat emittance device covered on blue-reactive phosphor compounds.
I don’t know of others are annoyed or notice the nauseating tint shift in the beams of nearly 70% of the LED flashlights equipped with Cree LEDs ever sold in the last 8 ~ 10 years, but i noticed that Cree has not really improved on this on most all their standard domed-LED emitters. Most all XP-G, XP-G2, XM-L, XM-L2, XP-L, XHP-50 & XHP70 ( and the V2 versions) have a bad tint-shift through the viewing angle of these domed emitters. Sadly the newest XHP & XP-L series LEDs have the worst angular-tint shift. ( one reason i have not been able to like the XHP series of LEDs over the MT-G2.)
The Cree MT-G2 probably has the least angular tint shift of any Cree LED ever made, and the High-Intensity (HI) versions of the XP-L and XHP-35 are not bad & much better than any domed Cree LED.
Cree domed LEDs in any shallow reflector, (like the original Olight Baton S10 & S20 lights) that were designed so badly that the tint shift made the beams look like a nauseating green radioactive booger hue.
The same goes for lanterns i built & modded with various LEDs. I sand the domes with 600-grit water paper to reduce that tint shift radiation in reflector-less lanterns. For example, if you take any domed Cree LED, (except the MT-G2) and power it up on a star with low amperage so it don’t over heat, then look at it at the various angles you will see it changes its tint color from a blue/white from the front, to a slight neutral white at 45 degrees, to a horrible cancer-causing green puss colored hue at 20 & less degrees to the side.
It seems that most people have grown to not notice it & gotten used to it. For example, if you take any of your domed Cree MED flashlights now & shine it on a white wall. Notice how the corona is likely a blush hue, then closer to around the hot spot it becomes more of a yellow or greet hue, then the hot spot is the intended tint (in “K”) to what the tint of the LED was offered as? now if you have a MT-G2 or Nichia 219 flashlight & do the same, the corona through the hot spot are closer to the same tint of white is supposed to be.
I seem to be more sensitive to this horrible tint shift than some others i feel. Every flashlight beam shot that i seen with a XM-L, XP-L, XHP-50 or XHP-70 domed emitter in it i nearly vomit. I only have one flashlight in my massive arsenal that has a XHP-70.2 in it, and that’s the Imalent DX80. I have not converted that to MT-G2s yet because of the cost of eight of them, (roughly $ 185 bucks for eight G0 5000K MT-G2 tax-in to upgrade the DX80 to eight MT-G2 emitters.) and the work to do the conversion. (added that the sheer lumens and wall of light that thing shoot out at 32000 lumens i don’t really care in that case) but either way i still irk at the tint.
Below are some photos showing how bad the angular-tint-shift is in Cree domed LEDs. (a Cree XM-L2 3B 5000K neutral white, in comparison to a Nichia 219B 5000K, placed 90 degrees to a white wall surface, and second photo showing a generic Luxeon 5000K “bead” LED that has a better tint consistency than the Cree XM-L2 5000K & even compared similar to the Nichia, which is one of the reasons besides the high CRI why we like the Nichia 219-series emitters in the first place is the balanced tint range in the beam profile) As you can see there of the difference where the XM-L2 has the tint shift… Notice how the Nichia & Luxeon-Bead has a linear tint through its viewing angle while the XM-L2 does not?
- I will test a MT-G2 & some HI-series of Cree XP-L soon in this manner to compare.
Lets hear your thoughts after you compare your Cree domed-LED lights to any Nichia or MT-G2 flashlights you have.
I have not tested any of the new Samsung 3535 emitters though yet to see their level of Angular tint-shift if they suffer from that…
