First thank you Apple for your sterling efforts."let's kick it up a notch!"
I've put together an interesting set of photos for you all to compare.
That's a lot of pictures and a fair number of lights.
My impressions: from using them, I still feel like the HDC EDC high CRI is KING for color rendition. I dream of a McGizmo Sundrop to compare (one day, perhaps!) but for now this is my king. However, for different uses, I prefer different lights. My Preon 2 Warm (which, some have noted, may be more towards white/neutral than other units) is my favorite light for looking at skin and mucous membranes. It brings out the erythemas of vital tissue like no other, and it's beam profile suits me well. For reading and close work, my H501w from Zebralight is amazing and my go-to light. I love my H51c and the high CRI is great and the tint is great, but for the way I personally use a headlamp, it's harder for me given the beam profile... I think that when the H502w comes out (with an XM-L!), that may finally move the H501w over...
Thank you guys and I can't wait to hear thoughts!
Using the fixed Daylight white balance was very helpful for us to see in "reference" to "daylight".
So one can see this run of 4Sevens High CRI are Warm Whites -
probably around 3200K or just a shade cooler (but not much) the variance we're seeing when compared to the previous (1st gen) 4Sevens Warm white could easily be within a single bin.
CRI is not that simple to understand - and I claim no expertise in it -
However CRI is always in reference to a "black body" radiator of the same color temperature - so for a cool white or a white that approximates to sunlight - those would be compared to the "black body" of actual "Daylight" or "Sunlight" - this is not as easy as it sounds since those are nature and can easily vary from day to day and season to season - so the CIE has developed standard "whites" of D65 (normally called daylight at 6500K) and D50 (@ 5000K which is actually a shade warmer than noonday sun only (no sky) which is normally regarded as 5500K).
Artificial light - at one time the most prevalent household lighting was/is tungsten light - about 2700K - just from this color temperature alone one knows this has to be significantly warmer tint/color than daylight or sunlight.
However the BIG trick for CRI for artificial light - is the approx black body for tungsten lighting is actually the tungsten light itself - so by definition a tungsten light bulb has CRI=100.
Yet just about everybody knows that it is very hard if not impossible to read certain shades of yellow printing on white and really difficult to distinguish navy from black (try picking these socks in household lighting).
So what's the value/worth of CRI in this instance -
well we can say if a light renders color the same way or how much it deviates from a tungsten bulb....
is that worth anything?
In Apple's case for medical type application - perhaps because traditional inspection lights have just about all been tungsten based - so a light that approximates to tungsten is "good" -
BUT think on this what if a light emphasized certain color like reds and orange - so that certain anomalies get highlighted/emphasized by the light may be better for that type of inspection - but since that would deviate from a tungsten light, the CRI by definition would be lower, and could actually be abysmal - yet I would think it may actually be more useful than a High CRI warm white that approximates to tungsten (to get the High CRI).
Take another rather silly example just to illustrate my point - - UV dye detection - we will not see these under and normal light even with high CRI - yet using UV rich light - like some blue LEDs will make these visible - so which light do we actually see the UV dyes better with - obviously the UV rich light - but these will have CRI probably in the single digits - ie: pretty awful CRI......
Ah! I hear you all argue this is a silly example and taking a specialized case -
As far as I know medical practice is specialized, being able to see skin/flesh anomalies is a specialized study - most of us lay-people do not go round looking for those, with or without flashlights - so if a flashlight was designed and wavelengths tuned to highlight or emphasize those anomalies - I would bet their CRI would not be that good.......
so much for High CRI -
So as far I am concerned CRI is just not too well understood -
we are also too enamored with numbers - a CRI=100 may not always be "perfect" -
if it were why can't we see yellow print on white
or pick navy from black under a light that is rated CRI=100?