Puny LED flashlights (Not!) + COLOR RENDITION Comparison

[GuyZero]

This thread is the most interesting thing I've read all week! THANKS VT for all your work in this area! I wish so much that I had something factual/useful to add.

I'm especially curious about the ideas expressed in this thread about seeing better in 3-D in the woods with warmer tints, and about mixing red/orange LEDs with whites to improve 3-D rendering.

And so I'm curious, does anyone have two Fenix lights with identical reflectors and one of those Fenix red filter attachments? I wonder if you held the two lights side by side, one with the red filter, and played with the brightness settings of the two lights... Since the reflectors are identical (same pattern of light) and small (so they can be very close together) would this render an outdoor woodland scene with better 3-D accuracy, with out the red/white divergence being too distracting? Or would you ideally have one of them have an orange/amber filter? Or does the filter need to be a special "blue blocking" type? (I don't fully understand how the blue blocking lenses work).

The reason I ask is that I like to mountain bike at night, and I've been using a Fenix L2D RB100 on my helmet with great enthusiasm, but I have noticed the flattening effect in the woods. It's still an excellent bike light, but when you are moving fast through the woods on uneven terrain every advantage helps! After reading this thread I have visions of two L2D's on my head, one set on medium or low with a red filter, and having better 3-D vision.

Is this a viable idea, or am I just looking for excuses to buy more flashlights?

[Or, preferably both... ]

 

[UnknownVT]

I am not too sure how valid this is, as our eye/brain combination is a lot more flexible than a camera and can compensate for a lot of conditions - but FWIW -

The Socks Problem -

I used the two different kinds of navy blue sock, two different kinds of black sock, and a pair of grey socks to do this -
Daylight Control shot literally out in the daylight - in direct sunlight about 1:30PM Atlanta, GA, USA -

as one can see even under direct sunlight it's kind of hard for the camera to distinguish between the navy and black - of course it's too high contrast (background is white) and the camera has limited dynamic range - as most of us know this should not be a problem for our eyes.

So I cropped the photos to show mainly the socks -
then adjusted only the brightness and contrast - to get the balance that best shows any difference -
so each of the following shots has been adjusted differently just to optimize any difference that can be seen -
ie: this is the best difference the camera can show.

Fixed Daylight Balance -

AWB (Auto White Balance) -

Tungsten White Balance for the incand lights -

The LED (a particularly well tinted Rebel 100) seems to differentiate the middle pair of navy blue socks best from the black socks either side of it (even better than direct sunlight) - the right-most navy pair still in the bundle does not show as well - but I think that's just the angle of the lighting - this is for both Fixed Daylight and AWB.

The incands Xenon (in Streamlight Scorpion), and room lighting - obviously do terrible using the Fixed Daylight White Balance as would be expected - not only is there a huge yellow orange cast but the all the socks kind of look gray - with some color cast. But using either AWB or Tungsten balance - the Xenon does slightly better using the Tungsten balance over the AWB -
enough to be able to see the difference between navy and black which is what I do see in real-life -

But notice the room lighting (not as intense or "white" as the Xenon) - even with the best I could adjust the brightness/contrast the navy sock never attain any blue and just looks like a shade of gray......

Please let me know what you think?

 

[soffiler]

...I'm especially curious about the ideas expressed in this thread about seeing better in 3-D in the woods with warmer tints, and about mixing red/orange LEDs with whites to improve 3-D rendering...

The reason I ask is that I like to mountain bike at night, and I've been using a Fenix L2D RB100 on my helmet with great enthusiasm, but I have noticed the flattening effect in the woods. It's still an excellent bike light, but when you are moving fast through the woods on uneven terrain every advantage helps! After reading this thread I have visions of two L2D's on my head, one set on medium or low with a red filter, and having better 3-D vision....

I am also an enthusiastic mountain biker, and I do a lot of night-riding. I use a helmet-mount HID with 450 lumens, and a handlebar-mount Coast Focusing Lenser modded with a Seoul P4 that does better than 150 lumens out-the-front. And I still want more light. I ride with a fast group of guys and the thick forested terrain here in New England seems to suck up whatever light you throw at it.

I think the red idea is kind of interesting, but, if I were you and I was going to add a second L2D on my helmet, I'd say: Give me MORE LIGHT! Run them both on high and screw the red filter. Doubling your light will have a much larger effect on your ability to see the terrain than a bit of red will do to mitigate the flattening effect (which I agree does exist).

 

[soffiler]

Vincent:

The "Daylight control/Daylight balance" and "Daylight control/AWB" images both clearly show the rightmost pair of socks in the bundle is blue. But on the other hand, they do a poor job of showing the middle pair is blue.

The "Rebel 100/Daylight" and "Rebel 100/AWB" do just the opposite: the middle pair of socks is obviously blue, but now the rightmost pair in the bundle looks black.

I don't see much in the way of blue in any of the incan shots regardless of camera balance. You've made it clear, and I totally agree, that the camera doesn't necessarily see what our eyes see but I still think your results support the idea that LED lighting (or natural daylight) is superior at the task of differentiating dark blue from black.

 

[meuge]

I am also an enthusiastic mountain biker, and I do a lot of night-riding. I use a helmet-mount HID with 450 lumens, and a handlebar-mount Coast Focusing Lenser modded with a Seoul P4 that does better than 150 lumens out-the-front. And I still want more light. I ride with a fast group of guys and the thick forested terrain here in New England seems to suck up whatever light you throw at it.

I think the red idea is kind of interesting, but, if I were you and I was going to add a second L2D on my helmet, I'd say: Give me MORE LIGHT! Run them both on high and screw the red filter. Doubling your light will have a much larger effect on your ability to see the terrain than a bit of red will do to mitigate the flattening effect (which I agree does exist).

Actually, I think he'd be much better off if he mounted 2 L2Ds on his handlebars, as far from each other as possible, then aimed them to cross beams at 10-20 meters.

I think a lot of the "flattening" has to do more with single-source shadowing than anything else.

 

[soffiler]

Actually, I think he'd be much better off if he mounted 2 L2Ds on his handlebars, as far from each other as possible, then aimed them to cross beams at 10-20 meters.

I think a lot of the "flattening" has to do more with single-source shadowing than anything else.

Cool idea! Now you've got me thinking... I might just have to try something like this. I don't have even one L2D, never mind two, but I have two lights with remarkably similar beam patterns: SF G2L plus an older Pelican M1 modded w/ Cree. Both use OP reflectors. Tint is different, and G2L has a wider sidespill, but otherwise they are amazingly similar in a whitewall comparison.

Although, I really can't get them very far apart on my bars given the placement of the shifters and brake levers. By the time you get 10-20 meters away, I think they'd look like a single-source again. Still very much worth a try. I might be riding Thursday night if we get some colder weather back thru here and the mud from the January thaw stiffens up...

 

[UnknownVT]

The "Daylight control/Daylight balance" and "Daylight control/AWB" images both clearly show the rightmost pair of socks in the bundle is blue. But on the other hand, they do a poor job of showing the middle pair is blue.
The "Rebel 100/Daylight" and "Rebel 100/AWB" do just the opposite: the middle pair of socks is obviously blue, but now the rightmost pair in the bundle looks black.
I don't see much in the way of blue in any of the incan shots regardless of camera balance.

Right - I originally thought it was a simple matter of lighting angle - since the sunlit shots had what I'd consider optimum angle of lighting 3/4 up/down as well as side/side. Whereas the flashlights were mainly straight on.

But the colors in the daylight shots are much closer to the way I actually see them in sunlight - the LED shots seem to emphasize the middle blue pair - might be the dyes/pigments used that respond to a particular wavelength the Rebel is rich in or maybe it's a simple lighting level - the outer pair probably was not as well lit as the center of the hotspot?

I also have direct flash shots that "imitiate" daylight - these have more or less the same angle lighting as the flashlights - these are closer to the daylight shots as one would/should expect.......

As one can see from either the daylight or the flash shots that middle navy pair is particularly difficult to differentiate from black in the photos - our eyes/brain do manage better - but it is still quite difficult - different angled and good lighting is needed
- the LED actually enhanced the difference......

 

[GuyZero]

Actually, I think he'd be much better off if he mounted 2 L2Ds on his handlebars, as far from each other as possible, then aimed them to cross beams at 10-20 meters.

I think a lot of the "flattening" has to do more with single-source shadowing than anything else.

I've considered this as possibly part of the problem, but I'm not likely to switch to dual handlebar mounts, and here's why:

I ride with two lights - one of my helmet and one on my bars. The one on the bars is nice because it always aims at what's directly in front of the wheel so you can quickly glance down with out swiveling your head. But the Helmet mounted light is far superior for mountain biking, flattening effects notwithstanding, because it always points where you are looking. When you are in the woods in the dark, and you are about to come around a sharp corner, your bar mounted light doesn't look around the corner until you're already into it. You end up continually turning into darkness. This can be done (lots of people do it all the time) but once you've experienced the advantage of being able to aim your light around a corner before you get there you're very unlikely to go back to just bar lights.

But everyone is different, and I can respect a difference in opinion here. I suppose if you had close to 500 lumens coming off your bars in a good spread this might not matter so much.

But might question was about getting the best of both worlds - if putting a red and white light together on your head would give you a directional light with better 3D rendering capability...?

I have several Streamlight PPL's (this is what I use on the handlebars) and a sampler pack of colored lighting filters. If I can get out into the woods to night I might take a walk with them (one red, one white) and see what it looks like.

The only problem is that the SLPPL's have only one brightness setting, and they are very throw oriented. I feel like two Fenix's would be better to test with. Maybe I'll ask my boss if I can borrow his for an evening...

If it works out I'll report back!

Does anyone know, are the blue blocking lenses just brown/orange filtered, or is there some other special magic to them? For instance, do they just filter out everything outside of the brown spectrum (I'm not sure that's really part of the spectrum) or do they allow certain parts of the spectrum through in some special combination?

 

[GuyZero]

The Socks Problem -

Fascinating!

I don't know much about spectral reanalysis, but I do know a little about photography and white balance that might help in your quest...

Have you ever used a "grey card"? It's a photographic tool that's basically just a neutral grey card with no color tint that you can set your custom white balance too. This might help you simulate the brain's ability to adjust to different types of lighting.

With a Canon, basically how it works is you hold the grey card up in the area where your photography subject will be so it's in the same lighting. Then you fill the frame of your camera with the grey card and set your custom white balance with it. What the camera does is assume that what ever it's looking at should have no color tint and it customizes the filtering system to compensate for any tint that actually exists. It's far more accurate then the white balance presets that are built into the camera if accuracy counts.

You can also do this with a truly white sheet of paper, but a grey card is more accurate.

It seems that you're using tungston and AWB settings to try and approximate for the tint of the various lights. If you can get a hold of a grey card you can set a custom balance that would be nearly perfect for each light source. This may seem trivial, but in these tests we're specifically looking at how small differences in in the spectrum affect out ability to detect colors, so it could make a big difference.

A good photography shop should have grey cards, and some photography books will make their inside covers a neutral grey color for this purpose, if you have one of those. (My National Geographic Photography Field Guide has this feature).

Again, I'm fascinated by your "Blue Socks" tests, and by this whole thread in general! You are a true scientist! Keep asking questions!

-GZ

 

[Daekar]

I have two things to add to this discussion which will hopefully be helpful. First, I noticed this single-source flattening problem a good while ago, and as far as I can tell walking in the woods, two lights of whatever brightness or tint is definitely better than one. This flattening effect seems to be worse for me the closer the light is held to my eyes, meaning that headlamps seem to suffer this problem the worst unless they are multi-emitter like the 5mms on the PT Apex, which is OK but not great.​

Second, I feel that the ability for our eyes to "white balance" according to the prevailing light conditions may not have been given proper attention. It is my experience that the only way to accurately compare lights under realistic usage conditions is... to use them. What I mean by this is that each user must evaluate each light in such conditions that their eyes have time to adjust to it. As I experimented with my lights (see sig pic), I found that if my eyes adjusted to good-quality LED-sourced light (or the light from my Boxer24W) the colors and details were quite good and that my ROP/P60 seemed very orange/yellow/brown. However, if my eyes were adjusted to the light from my ROP/P60 the colors were good as well, and the LED/HID light seemed ghostly/blue/green. ​

The question to me, then is not "which is whiter," or "what has the most complete spectrum," but "which shows the most detail and accurate color after my eyes have adjusted?" For me, the answer was unexpected, raving LED fanatic that I am. As far as I can tell, with appropriately adjusted eyes, in any environment, inside or outside, regardless of season (leaves on trees or not), I can see more detail and color with my ROP than with even my Boxer24W, which came as a surprise, believe me. I suspected this after having the lights for a relatively short time but refused to believe the evidence of my eyes until I passed over a skunk in a field with the HID and suddenly saw it with the ROP - how could I have missed a blank and white lump the size of a small dog in the middle of a green field? It was the last straw of proof for me, you might say. Does this mean I'm going to abandon my LEDs? Heavens no! The other pro-LED arguments still stand as valid and I will remain interested in improving my collection as technology evolves - but it also means I'm seriously considering getting an N30 to supplement my collection, hopefully the 4200K bulb will help. This does mean, however, that for tactical operations with a weapon-light, I would still recommend an incan to those I love, with their safety in mind - picking out colors might not be important for my torches (I don't tend to pick out drapes or furniture by EDC-light) but in time-critical life-threatening situations, I'd personally choose an incan with adjusted eyes over LED with adjusted eyes. Of course, I'd make darn sure that my loved-ones had a good LED light too, so they wouldn't need to use the battery-sucking incan for mundane tasks - or if the incan failed/ran out of juice.​

 

[dulridge]

Actually, I think he'd be much better off if he mounted 2 L2Ds on his handlebars, as far from each other as possible, then aimed them to cross beams at 10-20 meters.

I think a lot of the "flattening" has to do more with single-source shadowing than anything else.

I'm not convinced about this. Using LED and incan lights, I will have better depth perception with the incans than the LEDs. Both single sources, and more than one pair of eyes testing this. I'm not good at distance estimation in ANY light, but I'm marginally less bad with incans of comparable output to LEDs. And this is not just my eyes though the pairs of eyes I've checked this against are all within a few years of my age (i.e., 40-55). LED lights seem to give a sort of 2D representation of the landscape, whereas the 2 incans I own (as opposed to 50 or so LEDs) seem to make the landscape more 3D.

Given that I'd rather buy LED lights than incans, this is odd.

Colour is not an issue for me - I used to make a living making colour photographic prints and got used to colour matching under monochromatic sodium light which is not easy. I am very good at this, regardless of the light source as I have become used to doing it. I do not find incan vs. LED colour rendition issues to be a problem - I do find 3D to be an issue, but then 3D is rarely an issue in a darkroom where I learned colour rendition and matching.

 

[cdosrun]

Unknown, thank you for all your work on this topic, I have been following the topic for since you started it and I think airing your dirty laundry was a fantastic start to the New Year

I think that the eye's ability to focus blue light has a bearing on the topic of depth perception with LED lights. I can't make a comment based on as much experience as many because my incandescent lights (Mag85R and ROP-Hi) are far more powerful than my brightest LEDs (Dereelight DBS/CL1H etc.) but even though I prefer the LEDs, I find the incandescent lights easier on the eye outside at night. As the eye is better at focusing red lights onto the retina (for proof of this, try to look at the a 'blacklight', the violet output always looks fuzzy; well to me at least) I think the depth perception is easier.

http://www.ncbi.nlm.nih.gov/sites/entrez?db=pubmed&uid=3364521&cmd=showdetailview&indexed=google

I am not sure if one can extrapolate from the linked abstract to a paper on chromatic aberration of the Human eye, but from the scant details available it appears that the eye is focused on blue wavelengths at shorter distances 0.4m) and progressing to green at the 3m ranges tested; if the 'trend' (insufficient data to call it that but, poetic licence) continued it could explain why it is easier to see at a distance with a longer wavelength light source.

As to colour rendition, I really think this is a more complicated issue because it is so difficult to incorporate the Human element into a test we are, by our own nature, a big variable.

I think Unknown has done a tremendous job of showing fallibilities in Human vision and perception. This could be akin to hearing though, at low volumes, it is common to boost the bass and treble (loudness control) to bring the sound back into line with what is heard at normal volumes due to the ear's non-linear response to SPL, is there a similar effect with vision?

Andrew

 

[UnknownVT]

and I think airing your dirty laundry was a fantastic start to the New Year

Yes I sacrifice comfort to serve CPF -
do you know cold my feet got without socks on?

I think that the eye's ability to focus blue light has a bearing on the topic of depth perception with LED lights.
....
As the eye is better at focusing red lights onto the retina (for proof of this, try to look at the a 'blacklight', the violet output always looks fuzzy; well to me at least) I think the depth perception is easier.

No, sorry the eye does NOT focus red well either - hence the problem a lot of people have seeing well under red light.

Well, there used to be a authorative paper on-line -

USAF Flight Surgeon's Guide Chapter 8
http://wwwsam.brooks.af.mil/af/files/fsguide/HTML/Chapter_08.html
this link is now broken and I can't find the paper on the web.

Anyway I have a saved copy - and from that - on Visual Acuity -

"Also, the refractive characteristics of the eye causes blue light to focus in front of the retina and red light to focus behind the retina, when compared to yellow light that is focused on the retina. In other words, when the eye is emmetropic for yellow light, it is myopic for blue light and hyperopic for red light. This difference in color refraction, known as the chromatic interval, causes some distortion of the image on the retina. On theoretical grounds, then, the elimination of the short wavelengths by a filter should increase the sharpness of an image. This would seem to be confirmed by the use of yellow filters in photographing distant scenes. Such filters absorb the short wavelengths and allow the long ones to pass. They do give sharper photographs of distant scenes. "

Surprise - for years I have been an advocate of using yellow light for dim situations (that's low light, not stupid ) as I said I've EDC'd a yellow Photon for over 10 years now......

 

[kosPap]

UnknownVT

You have started a good thing and we must be thankful for your contribution. But somehow and influenced by my photographic knowledge i am kinda lost...

There is one thing I disagree with regarding your B&W conversion method. Desaturating is not 100% accurate. You need to go another route. Converting to Lab color.

Assuming you use Photoshop here are the steps:

Image>Mode>Lab Color>
View>channels> unclick all the layers in the pop up window except the one that says lightness

Briefly put L,a,b color is the best color coding method. All colors are ploted IN a sphere. a & b are the latitude/longitute coordinates and L is the distance from the core and demonstrates lightness.

Now if you appply that method to the Mcbeth charts you will see a small difference in the output. I tried it myself

There are some more issues. One is the use of the various camera white balance settings...Hmmm to many calculations, too many variables & biases.

The second is that you are messing with color coding profiles. I forgot to check, but if your jpegs have a sRGB profile loaded things are a bit worst. sRGB is a compressed color palette narrower than others (Adobe RGB) which categorize colors with different methods....Usually converting to sRGB creates unequal shift in hue and saturation between colors!!!

Could you run another test? Dawn/morning rise light (yellow at about 3200K), noon light (at about 5000?), tungsteen interior light (around 2800K), LED light of a known bin and a Xenon source. Then photograph the McBeth in raw format and "flash white balance", open the image in PS and extract the lightness channel (this way you remove all color-reading bias).

keep up the good work, Kostas

 

[soffiler]

I ride with two lights - one of my helmet and one on my bars. The one on the bars is nice because it always aims at what's directly in front of the wheel so you can quickly glance down with out swiveling your head. But the Helmet mounted light is far superior for mountain biking, flattening effects notwithstanding, because it always points where you are looking...

Ditto that!

I ride with a helmet-mount 450-lumen HID, and a bar-mount 150-lumen LED. Before I added the bar-mount LED, I was running just the HID on the helmet (and before that, it was a 20-watt ~300 lumen incan on the helmet). Most night-riders I know use a helmet mount only, and the rest use both as I do. NOBODY I know rides offroad using a bar-mount only. You run into many situations where your bar-mount is not illuminating where you need to see. You mention corners, a good example. My favorite example is riding over fallen logs across the trail. As soon as you loft the front wheel over the log, your bar-mount light is illuminating nothing but the trees above, and there's a black hole on the other side of the log that you're about to drop your front wheel into.

BTW, I added the bar-mount light right after an epic crash. Leading a group-ride at night, I was swivelling my head to the side, looking for a trail junction I wanted to take. Moving at a decent clip, I ran headlong into an obstacle in the trail directly in front of me. Had I been using a bar-mount "low beam" it would have been obvious in my peripheral vision.

...But might question was about getting the best of both worlds - if putting a red and white light together on your head would give you a directional light with better 3D rendering capability...?

I am unconvinced that the mere addition of some red light will suddenly change the whole world from 2D to 3D. I tend to agree that incan looks somehow "better" and more 3D where LED (and HID) create that 2D "flattening" effect, but I feel it's a fairly subtle effect, not a night-and-day difference. Just my opinion. I also feel that doubling your light by using two where you've only got one right now (helmet) will have a greater impact on your overall ability to see (i.e. safely and comfortably navigate difficult terrain at speed) than adding some red. I feel, just my opinion, that throwing a LOT more lumens out has the effect of creating more reflections from marginally reflective surfaces (rocks, dirt, tree bark...) and it is that reflected light that actually enhances 3D. It's also why I prefer my HID over my incan...

... although I must admit this thread has got me thinking I might bring both incan and HID on my next night-ride and try to compare them. Happily, both lampheads are the same brand, using the same helmet-mount mechanism and power cord, so I can change them out on the trail very easily.

Does anyone know, are the blue blocking lenses just brown/orange filtered, or is there some other special magic to them? For instance, do they just filter out everything outside of the brown spectrum (I'm not sure that's really part of the spectrum) or do they allow certain parts of the spectrum through in some special combination?

I don't know for sure but believe the blu-blocking sunglasses are simply yellowish-orange filters that take out the blue part of the spectrum. No magic to it.

 

[GuyZero]

So I went out with my boss and his L2D and some colored filters last night to do some testing regarding adding red or yellow light together with the white RB100. The results were interesting...

I didn't have a whole lot of time so I only chose two colors of filter to play with. I have an old kit that I got years ago for my Mini Mag that included a red and an amber filter. I figured those must be good choices since Mag picked them.

I wrapped a strip of rolled over duck tape around the head of one of the Fenixes and left a little over hanging the end so I could easily, temporarily, stick the filters onto the end.

We walked out into the woods and did a few tests. There weren't many green leaves around, just some sticker bushes, but we did have some grass, some dirt, and some evergreen trees to shoot at.

First we tried the red filter and played with various intensity settings on the two lights. It wasn't that impressive, to tell the truth. It made the scene a little brighter, but not particularly more 3D.

Then we tried the amber filter and found that our favorite setting was full power on the amber light and medium power on the white light. This did produce a more 3D image to our eyes, but I would not call it dramatic. The biggest difference was how it seemed to make everything sharper, easier to focus on, and a little higher contrast. Leaves and evergreen bows stood out from the brown tree trunks. Dry grass suddenly showed a lot more detail, and the scene was also brighter, as you'd expect.

Using only the Yellow light also produced high contrast, but it was much dimmer and color rendition was very difficult. It was not very pleasing and I would not want to mountain bike with only yellow filtered light.

We also tried just using two white lights on full power, and that did create a lot of light, but it was still somewhat washed out looking. We preferred the white/yellow combination.

Also interesting to note is that the Fenix with the yellow filter on high appeared roughly the same intensity of light as the white Fenix on medium. I assume this is because much of the strongest part of the LED's spectrum
(the blue) was being cut out. So in a sense, what found to be the best combination was an even mix of white and amber lights of the same apparent intensity.

I find it interesting having just read VT's post quoting that yellow light provides the best focus for the human eye. That's exactly what We experienced when we added the yellow light to the mix: colors could still be distinguished but everything just seemed to snap into better focus.

This also makes me think that the inherently yellower light of an incan probably is the superior light for seeing things outside at any given intensity for the same reasons. But for biking you have to take into account the big, heavy, short lived battery packs that go with them.

I would like to actually do a test on a bike in the woods with both lights on my helmet, but from last nights tests I would say that an amber filtered light plus a slightly dimmer LED would make a great combination. I'm not sure if it's worth strapping two 2AA flashlights to your head though. I used to use a Streamlight PPL on my helmet, which was very heavy, and it worked fine, but it was sure nice when I switched to the MUCH lighter Fenix.

Maybe what I REALLY need to do is buy 2 1AA Fenix L1Ds for this... (My wife will be thrilled with me!)

Cheers,
-GZ

 

[UnknownVT]

There is one thing I disagree with regarding your B&W conversion method. Desaturating is not 100% accurate. You need to go another route. Converting to Lab color.
Assuming you use Photoshop here are the steps:
Now if you appply that method to the Mcbeth charts you will see a small difference in the output. I tried it myself
There are some more issues. One is the use of the various camera white balance settings...Hmmm to many calculations, too many variables & biases.
The second is that you are messing with color coding profiles. I forgot to check, but if your jpegs have a sRGB profile loaded things are a bit worst. sRGB is a compressed color palette narrower than others (Adobe RGB) which categorize colors with different methods....Usually converting to sRGB creates unequal shift in hue and saturation between colors!!

Many thank for the input -

However I think you're reading way too much into what I intended.

All I really wanted to do was to show the main differences between modern LEDs and xenon incands by visual comparison.

None of the photos were meant to be for any measurements.

DeSaturation is the simplest removal of color (without panchromatic bias like converting to greyscale or taking the photo in black & white) as it literally desaturates/removes the color - L.A.B. may be a bit more "accurate" - but I don't think the relative difference is that great - at least I don't think to the point where any of the results would be adversely affected.

The simple white balance as found on most digital cameras was all I wanted to use -
Fixed Daylight White balance - to show how lights actually are, when compared to "daylight".
Tungsten white balance - because I was asked to show the incands using this balance,
since our brains compensate/adjust for artifical lighting -
AWB (Auto White Balance) - I added this - just because the digicam I used had pretty good AWB.

Again I intended the photos only as a visual comparison -
so no calculations were ever involved.

sRGB or AdobeRGB - I used simple sRBG (editted to correct my mistake) - because it is the standard for most JPG/photos on the web -
attempting to show AdobeRGB on the web is going to cause exactly the the sort of color shift you mentioned.

I'm more than happy to be corrected, and/or improve the simple visual comparisons -
but I did not intend the use of a camera as a measuring instrument.

Perhaps you'd care to click on the links in my sig to see that I may have just a little experience in photography?

 

[kosPap]

Many thank for the input -

However I think you're reading way too much into what I intended.

All I really wanted to do was to show the main differences between modern LEDs and xenon incands by visual comparison.

Indeed and this is the way I did not say that results were invalid...My comments was on the method details....BTW isn't sRGB the web standard?

Perhaps you'd care to click on the links in my sig to see that I may have just a little experience in photography?

hmm I see we share the same passion for concert photography...You can follow the link in my sig to see mine...

 

[Daekar]

Anyway I have a saved copy - and from that - on Visual Acuity -

"Also, the refractive characteristics of the eye causes blue light to focus in front of the retina and red light to focus behind the retina, when compared to yellow light that is focused on the retina.

Well! That is helpful information, and begs other rhetorical questions:
1) Will warm-white emitters display any detectable improvement in vision sharpness when compared to say, cool or cold whites?
2) Are yellow-tinted sunglasses better for discerning details afar?
3) Is this the reason that roadsigns with a blue background are harder to read far away than an equivalent green sign?
4) Does this mean that reading by red light will give you eye strain?
5) Why do we seem to always pick the two worst colors, blue and red, for alarm-clock faces? (I can BARELY read the blue clock on the front of my computer from across the room... and no, it's not just me...)
6) Is that why the new blue LED-bars for police cars always look more like bright blurry points of light rather than bright sharp points? (It makes them look bigger and are more "visually magnetic" IMHO)
7) Does that mean it's better to have a yellow motorcycle than a red or blue one, if you're interested in being visible?

All out of questions for the moment...

EDIT: I'm back with more:
8) Does this mean we have a definite and irrefutable reason to claim that HID bulbs with color temperatures of 4200K/4300K produce more useful output for the same number of lumens than those with 6000K+?
9) Is this why the lines in the road are yellow? (At least the centerlines are in the US - I can't speak for the rest of the world as I haven't gotten a chance to visit anywhere else but Canada and Bermuda)
10) Does this imply that there might be visual advantages to developing a yellow stain for use in microscope slides?

I'm sure more will occur to me...

 

[soffiler]

Well! That is helpful information, and begs other rhetorical questions:
1) Will warm-white emitters display any detectable improvement in vision sharpness when compared to say, cool or cold whites?
2) Are yellow-tinted sunglasses better for discerning details afar?
3) Is this the reason that roadsigns with a blue background are harder to read far away than an equivalent green sign?
4) Does this mean that reading by red light will give you eye strain?
5) Why do we seem to always pick the two worst colors, blue and red, for alarm-clock faces? (I can BARELY read the blue clock on the front of my computer from across the room... and no, it's not just me...)
6) Is that why the new blue LED-bars for police cars always look more like bright blurry points of light rather than bright sharp points? (It makes them look bigger and are more "visually magnetic" IMHO)
7) Does that mean it's better to have a yellow motorcycle than a red or blue one, if you're interested in being visible?

Fascinating stuff, isn't it? I think this thread is really going somewhere.

My answers to your questions (even though they're supposed to be rhetorical)

1) Quite possibly yes. I've got a modded Pelican M1 using a warm-white Cree, and it's beam pattern is quite similar to my SF G2L using the stock SSC P4 but the P4 is more neutral/cool than the Cree. I am going to run them both on my bars for tonight's night-ride and test one vs. the other.

2) I think so, yes. That was the whole push behind the original "blu-blocker" sunglasses, and they really do seem to work. I've got amber, clear, and grey lenses for my Rudy Project sunglasses and often use the amber on cloudy days (when others might not think to wear sunglasses at all). Cloudy days equate to higher color-temperature i.e. more blue - they seem "gray" because the intensity is much lower than a sunny day. The amber lenses markedly sharpen up a cloudy day.

3) seems reasonable, yes.

4) "...when the eye is emmetropic for yellow light, it is myopic for blue light and hyperopic for red light..." Myopia is difficulty focusing on distant objects. Hyperopia is difficulty focusing on near objects. I think the answer to this question is yes.

5) dunno the answer to that

6) Yes again. I've noticed the same thing. First time I ever noticed the blurry-blue effect was years ago, attending rock concerts when I was younger. When the light man would illuminate the whole stage blue, suddenly, the whole scene was blurry, and it would pop right back instantly if switched to yellows or whites.

7) I ride a yellow motorcycle. My other two choices in that model and year were red or blue. ('05 BMW R1200GS) Funny you should mention that!