Which has the highest CRI? (Just for fun)

Why link to a post when you can just copy it so no one has to follow the link?

1. Didn’t plan this quiz. Already started there. The comments and opinions are very interesting and spark interesting topics.
2. I want all the discussions grouped in there. To make new visitors know what we were discussing

- Clemence

Who can explain to me which rule was broken in post #3?

Please tell me RC

- Clemence

Someone reported my post, and I don't have the foggiest idea why.

Definitely not me RC because I knew it was a good intention. I rarely use that button. I usually just post my expression or simply use PM. You can ask SB.
Few days ago I accidentally clicked that button while tried to push the post number (“#xxx”) at far right corner of the post box. That could be your case too

- Clemence

I'm glad it wasn't you.

I don't think so.

After clicking the report button, you have to confirm that you really want to report the post.

Well, I clicked the spam button. Off course I clicked back button immediately. I don’t know if that counts or not.

- Clemence

Do we need more votes? The test is very onesided.

Agree, looks like more votes wouldn’t yield different result. I’ll reveal the answer once the electricity goes back. It’s been 30 minutes out so far.

- Clemence

I was really hoping #4 would turn out to be a low-CRI light. It’s the obvious “correct” answer because the white shades in its image are actually white with equal values for R, G, and B. But the other three have some tint in their white areas — #1 is greenish while #2 and #3 are rosy.

But looking at the revealed answers, it doesn’t really fit the photos. Based on the measured Duv, #2 should be the greenest by far, but its image instead has a pink tint. And in person, #1 should look blue, but in the photo it doesn’t.

Usually when I photograph low-CRI lights with auto white balance, it comes out pure white. And when I photograph high-CRI lights with auto white balance, they tend to have slightly off-white shades. The result says more about the white balance algorithm than it says about the emitters.

Wait, I’ll publish the RAW files for anyone to check it. I used DxO Optics software for the conversion along with it’s built-in color rendering index profile. Stitching done with ACDsee.
EDIT: pic #2 is not rosy, it’s brownish actually

- Clemence

Why I can’t post google drive links in here? I always returned back to blank post

Ah, no more than a single link

Here you go TK:
https://drive.google.com/open?id=1mge2dx6qvCSkYAWcQ6ER1GLScdYjawxC

- Clemence

I'm voting for all the above .. because that would just be sneaky .

#5

This was more of a TINT question since the CRI is very high and indistinguishable.

But the difference in tint is very very evident. Ant that is why the optisolis won hands down. That is some amazing tint neutrality. Amazing LED.

Using the white section in the upper-right corner of the image, blurred to get an average color, the values I’m seeing are:

  1. R,G,B = 233, 238, 232
  2. R,G,B = 246, 243, 238
  3. R,G,B = 243, 239, 234
  4. R,G,B = 233, 233, 233

Normalized to 100%, the values are:

  1. 97.9, 100, 97.4 (greenish)
  2. 100, 98.8, 96.7 (pinkish)
  3. 100, 98.4, 96.2 (pinkish)
  4. 100, 100, 100 (pure white)

This is why I assumed #4 would get the most votes… because it’s actually white. However, I also guessed that #2 or #3 would be the ones with the highest CRI because lights with high R9 values usually show up a bit pink in pictures.

If #2 has a +0.0038 Duv and #3 has a –0.0011 Duv, but they have nearly identical pink-ish tints in photos, that basically means there was an error on the camera or in post-processing. Accurate color temperature correction would have produced different results for #2… something like this:

  1. 97.9, 100, 97.4 (greenish)
  2. 94.0, 100, 94.0 (green)
  3. 100, 98.4, 96.2 (pinkish)
  4. 100, 100, 100 (pure white)

… and in this case, the 92.5 CRI emitter in photo #2 would produce worse photos than the 74.8 CRI emitter in photo #1, because its tint is more green.

Thanks for the thorough inspection TK. I did nothing but take the pictures, convert, stitch, and upload. You can check the EXIF data to double check if it’s the camera or the post processing that cause errors. I took each picture twice using the camera built in double exposure. This is the only quick way to get even lighting without making a dedicated lightbox. I only use 5600K WB because this is what I’ve been using since the first time I uploaded pictures in BLF. I like consistency
If anyone think I must redo the supposed to be “Just for Fun” quiz, I’ll do it no problem. Didn’t mean to misled anyone, it is what it is. Don’t forget to include monitor limitation into consideration.

- Clemence

… those all used 5600K white balance?

The differences should look pretty dramatic unless they were re-balanced at some point. There’s no way a white sheet actually turns out pure white when the light source is 4852K and the camera is 5600K, even if the CRI is 100.

No, of course not. :slight_smile:

It’s just kind of a recurring topic with a long history of debate. Some people insist CRI can only be seen in person, others insist it can be seen even after passing through a camera, a 3-channel image file, the internet, and a 3-channel screen.

Me, I think CRI is pretty noticeable in person but basically impossible to represent accurately onscreen.

Er, unless a spectrometer is used, I mean. That allows us to get around the 3-channel limit.

That’s exactly what I said in the beginning of the quiz. I was kind of surprised the picture showed the real highest CRI. Because to me it’s the tint that made it stands out, not the color vividness. Only #1 pic easy to guess, the rest are near identical except for the tint. Yes, all shot in 5600K WB. The information can be found in the EXIF RAW files like this:

JFIFVersion - 1.02
X-Resolution - 1 dpi
Y-Resolution - 1 dpi
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ISO Speed - 200
Sensitivity Type - Standard Output Sensitivity
Exif Version - 0230
Date and Time (Original) - 2019:01:09 22:27:34
Date and Time (Digitized) - 2019:01:09 22:27:34
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Max Aperture Value - 3.5
Subject Distance - 0.24 m
Metering Mode - Multi-segment
Light Source - Other
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File Source - Digital Camera
CFAPattern - [Red,Green][Green,Blue]
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Exposure Mode - Manual
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Digital Zoom Ratio - 1
Scene Capture Type - Standard
Gain Control - Low gain up
Contrast - Low
Saturation - Normal
Sharpness - Soft
Lens Info - 12-50mm f/3.5-6.3
Lens Model - OLYMPUS M.12-50mm F3.5-6.3
Special Mode - Normal, Sequence: 0, Panorama: (none)
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Lens Firmware Version - 1.102
Max Aperture At Min Focal - 3.5
Max Aperture At Max Focal - 6.3
Min Focal Length - 12
Max Focal Length - 50
Max Aperture - 6.2
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Flash Model - None
Flash Firmware Version - 0
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Preview Image Length - 804837
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Focus Mode - MF; MF
Focus Process - AF Not Used; 0
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AFPoint Selected - undef undef undef undef
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Sharpness Setting - –1 (min –5, max 5)
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Picture Mode - Muted; 2
Picture Mode Saturation - 0 (min –2, max 2)
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Picture Mode Sharpness - 0 (min –2, max 2)
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Picture Mode Effect - Standard
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Drive Mode - Single Shot
Panorama Mode - Off
Image Stabilization - On, Mode 1
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Manometer Reading - 0 m, 0 ft
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Raw Dev Version - 0100
Raw Dev Exposure Bias Value - 0
Raw Dev White Balance Value - 0
Raw Dev WBFine Adjustment - 0
Raw Dev Gray Point - 0 0 0
Raw Dev Saturation Emphasis - 0 0 0
Raw Dev Memory Color Emphasis - 0
Raw Dev Contrast Value - 0 0 0
Raw Dev Sharpness Value - 0 0 0
Raw Dev Color Space - sRGB
Raw Dev Engine - High Speed
Raw Dev Noise Reduction - (none)
Raw Dev Edit Status - Original
Raw Dev Settings - (none)
Image Processing Version - 0112
WB_ RBLevels - 256 256 256 256
WB_ RBLevels3000 K - 158 456 256 256
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WB_ RBLevels3600 K - 200 332 256 256
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WB_ RBLevels4300 K - 226 298 256 256
WB_ RBLevels4500 K - 240 298 256 256
WB_ RBLevels4800 K - 242 274 256 256
WB_ RBLevels5300 K - 256 256 256 256
WB_ RBLevels6000 K - 280 230 256 256
WB_ RBLevels6600 K - 288 242 256 256
WB_ RBLevels7500 K - 304 200 256 256
WB_ RBLevels CWB1 - 200 400 256 256
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WB_ RBLevels CWB3 - 196 218 256 256
WB_ RBLevels CWB4 - 196 218 256 256
Color Matrix - 392 –108 –28 –60 372 –56 6 –104 354
Black Level2 - 0 0 0 0
Gain Base - 256
Valid Bits - 12 0
Crop Left - 8 0
Crop Top - 8 0
Crop Width - 4608
Crop Height - 3456
Sensor Calibration - 3706 256
Noise Reduction2 - (none)
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Camera Type - Mirrorless Camera