Visibility - Lumen - CRI

clemence · 2019-07-31T22:00:20.000Z

Based on Maukka and Djozz measurements. Color filter including your eye glasses, can increase or decrease CRI. The easiest example is the minus green filter. It even out the greeness to make the rest of the spectrums (if any) stands out more. CCT and CRI are the result of spectrum balance.
In your case, it’s blue filter. I haven’t seen any test result about it. To my understanding, filter can only reduce but won’t add anything that isn’t there in the first place.
@SKV89, could you help us to measure filtered low CRI 6500K lights you have? Thanks.

[Clemence]

koziy · 2019-08-01T03:40:58.000Z

I don’t agree with the common BLF dogma that says high CRI makes things easier to perceive or recognize. For decades, people watched movies on low resolution televisions with literally no colors and they were able to recognize everything on the screen. With flashlights, I have literally never found myself actually unable to recognize or taking even a millisecond longer to recognize any single object in the world because the flashlight used to illuminate it was “low CRI.” OK, so reds are a little dimmer in low CRI light, it’s just something you get used to. The color of sunlight changes throughout the day and is different still when it’s cloudy, and humans have evolved to continue to recognize items in the world even with these slight changes, so it’s not clear to me how messing with the colors to such a small degree is supposed to affect cognition.

That said, high CRI LEDs are absolutely better than low CRI LEDs. On knife forums, enthusiasts talk a lot about their high carbon steels or ultra hard stainless steels. Well, high CRI is kind of like that. It tends to be a desirable feature because, even though the difference doesn’t have a huge amount of practical repercussions over something more basic (or rather, there are benefits, but they tend to be diminishing returns), it’s still more pleasant to use high CRI flashlights. The color of light tends to affect our mood, and the technical accomplishment of formulating an LED that approximates sunlight so well is cool in itself. There are certain practical advantages, like in medical use, although not everyone will really care about the actual advantages like that. Mostly, it’s just that a good high CRI emitter tends to produce light that “looks better”than an inferior product.

The same goes for brightness. Even though a 300 lumen flashlight is about as bright as the average handheld user will ever practically need, we still want the ability to shine 3000 lumens, 30,000 lumens or, someday, 300,000 lumens, if only because it’s a technical accomplishment and it’s cool. It doesn’t matter that the human eye doesn’t perceive light linearly, it’s still something that enthusiasts want because it’s “bigger and better” than what was available last year.

Joshk · 2019-08-01T04:16:06.000Z

In the early days of TV, people on TV wore clown-like makeup to exaggerate skin tones so they looked “correct” on an early TV.
Heck, Nixon is agreed to have lost a 1960 debate because he refused to wear makeup when offered and therefore looked “unhealthy” compared to Kennedy, who wore makeup.

SammysHP · 2019-08-01T04:36:24.000Z

In some situations low CRI lights are like color blindness. Walking through a forest and everything looks like the same gray/green/brown isn’t fun.

koziy · 2019-08-01T05:02:53.000Z

SammysHP:

In some situations low CRI lights are like color blindness. Walking through a forest and everything looks like the same gray/green/brown isn’t fun.

Gray, green and brown are the primary colors found in forests, though. Human low light vision is like color blindness for sure, since our most sensitive light receptors in our eyes are not that good with colors, but if you’ve got a flashlight, you are not experiencing color blindness. Like….at all. These kinds of exaggerations just have the effect of encouraging people new to the hobby to spend lots of money to finally find out what “HD vision” is like, since so many people on this forum use that term and supposedly experience it.

hasddie293 · 2019-08-01T05:05:57.000Z

SKV89 found disagree, :laughing:

SKV89:

The yellow shades will not increase CRI. It just blocks out the blue wavelengths.

Clemence found agree…

clemence:

Based on Maukka and Djozz measurements. Color filter including your eye glasses, can increase or decrease CRI.

until then, what benefit most of using yellow lens/shades is that, it can reduce eye fatigue or itchiness base of what I’ve been experience. Also on my own thought, lumens in 6500k is higher than 3000k which absent of blues, but with shades lumens stays the same. Yeah this is my own opinion, try your own and I’m sure out there someone own 6000lumen. TRY wear yellow glass and lights up your flashlight on turbo! see if you know what i mean…

The only disadvantage of using Glass/shades is during rains. glass often get wet and block.

SKV89 · 2019-08-01T05:26:23.000Z

clemence:

Based on Maukka and Djozz measurements. Color filter including your eye glasses, can increase or decrease CRI. The easiest example is the minus green filter. It even out the greeness to make the rest of the spectrums (if any) stands out more. CCT and CRI are the result of spectrum balance.
In your case, it’s blue filter. I haven’t seen any test result about it. To my understanding, filter can only reduce but won’t add anything that isn’t there in the first place.
@SKV89, could you help us to measure filtered low CRI 6500K lights you have? Thanks.

[Clemence]

I’ll find a green filter and test it and post the results.

ZoomieFan · 2019-08-01T07:25:11.000Z

hasddie293:

Also on my own thought, lumens in 6500k is higher than 3000k which absent of blues, but with shades lumens stays the same.

Colored shades filter or not.
If light get’s filtered it get’s less bright.
Say you have an RGB light that draws 10 amps. Then you filter away the RG. The light still draws 10 amps but the RG light is gone.

Those yellow glasses are interesting. I’ve seen them advertised as being able to look better through fog.
I use them for fishing and the can make a huge difference.
A while back a clear river, about 10 feet deep. A dozen catfish on the bottom. A sunny day but the reflection of the water wasn’t bad.
With the glasses on I could see the catfish at least 3x better.
I have no idea why but it makes a real difference. Not just something that can only be measured in lab.

And that’s why I posted my original question.
The thing with YouTube reviews and pictures is always that camera settings may mess up the results.
Below the Convoy BD04 at differnt color temps. Not an high CRI led. But study the details.
The 3000K looks like having the most contrast on the leaves. The 7000K washes out colors.
Does that make the 3000K light always better? I think it depends on what colors the scenery has.
In this case mainly green. How different would it be if the it were not green bushes but red roses?

The bench has superior contrast at 6500K, but is totally white.

Maybe “the best” depends on what you use the light for.
I’ve read that those mountainbikers that race from a hill in the dark prefer lower K because the eye responds quicker to it.
A guard may prefer 6000K because all he wants is max brightness to see if someone is on his turf.

Anyway if color temps make a diff in contrast and brightness, then CRI may add to that mix too.
I would be suprised if it doesn’t….

clemence · 2019-08-01T08:42:16.000Z

All pictures below taken with Manual mode and used same WB. speed, and aperture
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[Clemence]

Tally-ho · 2019-08-01T16:42:56.000Z

SKV89:

clemence:

Based on Maukka and Djozz measurements. Color filter including your eye glasses, can increase or decrease CRI. The easiest example is the minus green filter. It even out the greeness to make the rest of the spectrums (if any) stands out more. CCT and CRI are the result of spectrum balance.
In your case, it’s blue filter. I haven’t seen any test result about it. To my understanding, filter can only reduce but won’t add anything that isn’t there in the first place.
@SKV89, could you help us to measure filtered low CRI 6500K lights you have? Thanks.

[Clemence]

I’ll find a green filter and test it and post the results.

Clemence was not mentionning a green filter but a minus green filter. The denser Lee minus green filter approximates a CC30 magenta camera filter.

hasddie293 · 2019-08-03T06:07:00.000Z

How about this one, welding… see it produce lights that so bright. I wonder how much lumens was that and what CCT level? ? From my bare eyes observation, that looks like, my guess 6000lumens or more with 6500k… I do recall a flashlight that can burn paper, acebeam??

but, the key things here is, that guy is using black shades to cover his eyes from looking direct EXCESSIVE amounts of lights that going to cause blindness. 2nd he used shades so that his eyes can filter trough a Ultrahigh brightness situation which make him able to see thus manage his task which is to welding…barely see though

Now, isnt’t that ultra high brightness flashlight can be dangerous? would love to hear from you all…

SKV89 · 2019-08-03T06:43:47.000Z

clemence:

Based on Maukka and Djozz measurements. Color filter including your eye glasses, can increase or decrease CRI. The easiest example is the minus green filter. It even out the greeness to make the rest of the spectrums (if any) stands out more. CCT and CRI are the result of spectrum balance.
In your case, it’s blue filter. I haven’t seen any test result about it. To my understanding, filter can only reduce but won’t add anything that isn’t there in the first place.
@SKV89, could you help us to measure filtered low CRI 6500K lights you have? Thanks.

[Clemence]

I learn something new everyday. These minus green filters do increase CRI and R9. Wow!

Acebeam TK16 w/ Oslon White Flat emitters
CCT: 6180K
DUV: 0.0038
Ra (CRI): 67.1
R1: 67.1
R2: 69.1
R3: 69.0
R4: 69.5
R5: 68.5
R6: 59.7
R7: 74.4
R8: 59.1
R9: –34.1
R10: 25.7
R11: 69.4
R12: 36.1
R13: 65.9
R14: 82.3
R15: 60.7
Rf: 63
Rg: 96

Acebeam TK16 w/ Oslon White Flat emitters and Lee 248 Half Minus Green Filter (Y=72%)
CCT: 5774K
DUV: –0.0129
Ra (CRI): 77.2
R1: 83.8
R2: 79.0
R3: 72.1
R4: 78.7
R5: 83.5
R6: 71.5
R7: 77.1
R8: 71.5
R9: 14.0
R10: 47.4
R11: 83.1
R12: 53.4
R13: 80.7
R14: 83.4
R15: 79.5
Rf: 66
Rg: 103

clemence · 2019-08-03T06:44:54.000Z

hasddie293 · 2019-08-03T07:06:17.000Z

SKV89:

I learn something new everyday. These minus green filters do increase CRI and R9. Wow!

Say whaaat!!! :partying_face: :+1:

Tally-ho · 2019-08-23T18:59:38.000Z

koziy:

These kinds of exaggerations just have the effect of encouraging people new to the hobby to spend lots of money to finally find out what “HD vision” is like, since so many people on this forum use that term and supposedly experience it.

Let’s take the FireFlies E07 as an example. The high-cri version with SST20 4000K CRI95 cost 20 dollars less than the one with XPL Hi V2 5A 4000K and lower CRI.
You don’t need to spend lots of money for “HD vision”.

On a side note : “Taken together, the present results indicate that a wider spectral bandwidth of illumination allows the visual system to focus more accurately. From an ecological standpoint this does not come as a surprise because natural objects possess broad spectral reflectance functions, and the eye is seldom confronted with narrow-band light. Even the spectral distributions of colorful objects can be relatively broadband. When sunlight reflects diffusely from these objects, the retinal image is composed of light of a spectrum of wavelengths. Thus it seems reasonable to speculate that the visual system might have evolved focusing mechanisms that operate best in the presence of broadband illumination”.
(Source : Spectral bandwidth and ocular accommodation (pdf)).

maukka · 2019-08-24T05:20:28.000Z

SKV89:

Acebeam TK16 w/ Oslon White Flat emitters and Lee 248 Half Minus Green Filter (Y=72%)
CCT: 5774K
DUV: –0.0129
Ra (CRI): 77.2

CRI isn’t really valid for this light source. The duv of –0.0129 from the BBL isn’t white as per the CRI standard (CIE 13.3:1995). Duv of +–0.0054 is required and that’s why some software have a warning regarding CRI measurements if the duv is too large.

But yes, theoretically CRI has improved.

zerodish · 2019-08-24T12:56:47.000Z

I worked in a photo lab for a while. I took some blue block filters taped them to my glasses and wore them around all day. For a while every think that was white looked yellow. Eventually my brain adjusted and every thing that was white looked white. Every thing that was blue looked black.

Unheard · 2019-08-24T14:50:30.000Z

I see a huge difference between Sofirn C01 and Fenix E01 when it comes to recognition. They are extremes, of course. It doesn’t necessarily has to do with the difference in color rendering quality only, I also notice this outside when walking or running using CW vs. NW lights. Armyteks low CRI warm lights are still slightly better than CW headlamps like my old Black Diamond Storm. Beamshots can reproduce that. CW illuminated scenes usually look flat to me. Likely this ist due to the relevance of distinguish shades of green as opposed to shades of blue.

JaredM · 2019-08-24T16:28:13.000Z

As Clemence has pointed out and experiments with Lee filters have shown, the proper amount of blue filtering can increase the CRI in low CRI, cold white emitters. Perceived brightness is a hard thing to debate here as there’s not a clear-cut way of measuring it. We have eyes that are effectively camera’s in ‘Full Auto’ - constantly adjusting white balance and exposure and focal length. I can see many sides of this topic/debate. For example, what one can say (and IMO be mostly correct) is that filters can’t ‘add’ anything and that - for certain - less light is reaching your ‘eyes’ while wearing the yellow lens glasses. However, what I don’t know is how the eyes respond to this reduction of blue-wavelengths in regards to pupil dilation. Will this decrease in lumens ‘at the front’ of the eye be offset by a larger pupil letting in more (basically the eyeball’s auto-exposure)? Thinking from this perspective, it’s possible that we could perceive in the right environment (think of a white room vs open field of dew covered grass) equal brightness with higher ‘CRI’. (CRI is in quotes because color fidelity is not equal to gamut and/or vividness)

Said another way, we would likely all agree that a beamshot comparison taken with a camera on Full Auto (with no read-out either ) would be inconclusive.

…

My experience and opinion for the blue-filtering (yellow lens) glasses is that they have certain applications that really do help visiblity. Driving at noon on a clear summer day is the best example from my experience. The effects are that the sky/horizon is darkened, and bright reflections and glare are reduced significantly, allowing you to open your eyes fully and also dilate the pupils. Objects on and alongside the road (heavy in red and green wavelengths) then seem ‘highlighted’ and you feel more ‘alert’.

Clemence (as always) provided some excellent examples with the photos in post #21. Let’s look at the last set of pictures - the ones of the bush against a bright, blue sky. The filtered image, even when viewed on a monitor, appears to ‘highlight’ the objects on the ground. In situations such as driving, this is beneficial. NOTE however these are taken with fixed exposure and WB. It’d be interesting to see them actually in AUTO.

…

Lastly, my 2 cents about ‘HD’ vision with high CRI/Rf/Rg is that it’s valid to an extent. Of course there are many, many people on the internet who will exaggerate anything and everything. Another fact is that everyone’s eyes and color acuity are different. Someone who is completely color blind will likely not be raving about their high R9 emitters, though someone like this lady with tetrachromacy may have a completely different opinion. In my n=1 experience, ‘good tinted’ hiCRI emitters provide significantly better visibility and pleasure (subjective), especially in my favorite environments where foliage, earth, and human skin are the main targets of illumination. As a result, I choose to spend my money nearly exclusively on hiCRI lighting products.

As an example of colors effect on visibility, I’ll once again refer to the images that Clemence posted of color vs grey-scale (post #3). The point of this comparison can be measured by the amount of time you have to look at the image to ‘feel’ like you mostly understand the environment. For me, it was 5+ seconds for grey images and probably about half for colored.

-Jared

jon_slider · 2019-08-24T18:14:20.000Z

ZoomieFan:

I posted that photo with the arrows that I added, to demonstrate to HDS people that the XPG3 sucks!
I will try to link you to my original post with that photo , though CPF is running hella slow and may not load atm… back in a flash… go through that thread, you will see a lot of pics showing how terrible the tint is of the XP-G3, and you will see Hogo display his ignorance about tint shift

so they tarred and feathered me and ran me out of town
after which I sold my HDS in disgust for the ignorance and fanboyism of that crowd

in any case, the owner of those lights admitted that the object at the end of the arrow is indeed a red frisbee, not a yellow one

so, what else do you need to know?
more lumens, showing the wrong color is imo, NOT better than less lumens showing the correct color

but HDS people just buy the most lumens, because people think lumens matter more than CRI… I feel the opposite

if its not High CRI, I do not care how high the lumens are… I dont want to harvest yellow frisbees, only to find out I chose a poisonous Amanita Muscaria by mistake, because my Low CRI, Green/Yellow tinted XPG3 misled me

.

Now about filters
If you filter an LED that already has negative R9 (red output), the filter cannot add Red that is not already there, it will just make things marroon, or some other non Red color

so the bottom line, for me, is to start with a High CRI LED with High R9 (Red) output

then if you want to massage the tint, filter to your hearts content

more lumens of negative R9 wont make the light produce Red that it cannot produce

dont kid yourself, a filter over a low CRI LED will NOT match the color rendering of a High CRI LED with high R9 output

here is some more info about the XP-G3 that I love to hate

The XP-G3 and the mystery of the disappearing luminance Flashlight Modding and DIY Parts

The XPG3 created a lot of excitement when it was first tested because of its high output and low Vf. With a die area very close to the XPG2 but with more output, the XPG3 was anticipated to beat the XPG2 for thrower applications. But the performance of the XPG3 in flashlights was disappointing in some ways: the measured throw when dedomed was significantly less than the dedomed XPG2 and there was a pronounced angular/spatial “tint shift” in the beam which was distracting and hindered object iden…