What is the best flashlight in the fog?

[Magic Matt]

They are both tight beams with similar intensity or lux. Of, course they are not the same. One is LED. The other is incandescent. And the bluish one is not a blue incandescent.

I think you missed the point somewhat.

You have only hit 2 out of the 3 requirements for a valid test.

Very similar, or identical, beam patterns - Pass, just.

Very similar, or identical, measured brightness in the beam - Pass.

Very similar, or identical, colour temporature and tint - FAIL

The comparison is not valid unless the tint is the same, because the tint makes a large difference to how well the fog is penetrated. Cool white lights sources are crap in fog, regardless of whether they are incan, LED, HID, or glow-in-the-dark alien urine.

If you take two IDENTICAL LED flashlights, one with a warm white, and one with a cool white, the warm white penetrates more and looks better. That's an undeniable easily observed fact. Comparing a cool white LED and a warm white incan doesn't prove anything outside of what we have already observed - warm white is better in fog. A cool white incan would in all likelyhood look just as bad as a cool white LED.

 

[Icebreak]

1.) As can be seen in this thread, opinions very unless they are ignored.
2.) It ain't just tint.
3.) What you see is what happens in reality with real flashlights.
4.) Go do some real world "valid" beam shots of your own and get back to us.

 

[defloyd77]

use your imagination, be creative, :duh2:
i made few lights from automotive lights, back in the days when there was not much else to work with, it came out not bad at all, turned out to be handy searchlights.
todays kit lights for cars a lot more lighter and smaller. you don't have to use led acid or nicd batteries, now there is a lot more possibilities,
another question is it the best way??? idk , but one thing is for sure lights will be made specifically for fog

Keep in mind what automotive fog lights are for and where they are mounted, way below eye level.

You know, I'd love to see some comparison shots of blue objects in the fog using cool tinted LED's, neutral LED's and incans. These shots on here so far are an unfair comparison as warmer tints already have the advantage of making those colors pop out when there isn't fog.

Beamshots with say a blue house being lit up with each type light could very well prove my previously mention "high contrast backscatter" theory. If my theory is correct, the warmer tinted will have greater contrast with the blue house than the cool tint, which will give the same effect of the pictures in this thread.

 

[Magic Matt]

This is not intended to be personal critisism of you, or any sort of attack on your credibility. I am merely trying to inject an element of scientific analysis and criteria, which is what is needed to actually answer the subject of this thread. Unfortunately, that means you have to be somewhat clinical in analysis, and whilst your efforts are appreciated, the gathered evidence isn't up to drawing much by way of conclusions.

1) Not quite sure what you're trying to say there... if it's that we have different opinions, then I dispute that slightly, although I realise some may consider it a pedantic point. We have different theories as to what makes a good flashlight for use in fog, but ultimately only valid and scientific experimentation will yeild a difinitive answer.

2) I never said tint was the only affect, but introducing such a massive flaw into the experiment from the outset just makes any conclusions you draw open to massive interpretation. I am well aware that CRI is also a factor, but a cool white tinted LED will have a massively different CRI to a warm white tinted one anyway, so that just adds more credibility to disputing the comparison. There's actually enough of a difference in your beam shape there to also affect clarity, but the most noticable factor is the beam tint - I would say the incan actually has a dark spot in the centre, which may possibly mean that the target is illuminated more from scattered light than it is direct light. If you want to draw a conclusion as to a particular parameter, you need to reduce all the other factors to virtually zero - your two shots have quite a few differing factors, so you can't conclude it is down to one factor. We already know tint as well as beam shape makes a large different, so both need to be eliminated to refine the tests and further our understanding. Another factor which unfortunately is beyond control is the density of the fog... is there a way to measure that?

3) We need proper comparisons as a frame of reference, yes. Photographs with the camera on the same settings for both are a good start, providing the light sources are comparable. I have already stated why, in this case, the comparison lights aren't close enough in real world output to draw much of a conclusion.

4) I don't have enough light sources to do many comparisons, but I do have a camera with proper colour calibration setup from an industry recognised Kodac colour chart at all ISO and Shutter combinations with the different lenses I use. I also have access to a 'dark site' where there is virtually no light pollution present. I would be more than happy to do beamshots in cooperation with somebody who could provide flashlights. The biggest issue I would have is actually that we get very little fog in controlled conditions - it tends to be somewhat unpredictable! There seems little point in me posting beamshots of a common flashlight in commonly occuring conditions on this forum, there are already plenty if you use a search.

 

[defloyd77]

2) I never said tint was the only affect, but introducing such a massive flaw into the experiment from the outset just makes any conclusions you draw open to massive interpretation. I am well aware that CRI is also a factor, but a cool white tinted LED will have a massively different CRI to a warm white tinted one anyway, so that just adds more credibility to disputing the comparison. There's actually enough of a difference in your beam shape there to also affect clarity, but the most noticable factor is the beam tint - I would say the incan actually has a dark spot in the centre, which may possibly mean that the target is illuminated more from scattered light than it is direct light. If you want to draw a conclusion as to a particular parameter, you need to reduce all the other factors to virtually zero - your two shots have quite a few differing factors, so you can't conclude it is down to one factor. We already know tint as well as beam shape makes a large different, so both need to be eliminated to refine the tests and further our understanding. Another factor which unfortunately is beyond control is the density of the fog... is there a way to measure that?

This is exactly the point I am trying to prove (I'm not doing to well at it, insomnia has that effect), that tint creates an illusion that the warm light shown in these pictures "cuts" through the fog better than cool tint, but simply the warm tints already have an advantage over cool at illuminating yellows, browns and greens over cool tints. Add to that illuminated fog that either "blends in" with the background(warm tint) or radically contrasts with the background (cool tint).

Okay I'm thinking way too hard on how to explain my theory Let's try this, the fog is there, no matter what kind of light you use, there is simply no magic way to see through it, all the warm tints are doing in these pictures is "camouflaging" the fog. Taking a picture of a cool LED against a blue background will have this same camouflaging effect.

 

[Cataract]

Not quite, where are we going to mount them? On our shins?

Screw them on top of the steel toes of your boots!

 

[defloyd77]

Screw them on top of the steel toes of your boots!

DUDE!!! THAT'S GENIOUS!!!

 

[Magic Matt]

Love it Cateract! If you mounted an LED directly to the steel toecap, you could use it as a heat sink and it would keep your toes warm in the cold too! :tinfoil:

 

[alpg88]

Keep in mind what automotive fog lights are for and where they are mounted, way below eye level.

damn, you right, i never thought about that.

 

[Outdoors Fanatic]

This is not intended to be personal critisism of you, or any sort of attack on your credibility. I am merely trying to inject an element of scientific analysis and criteria, which is what is needed to actually answer the subject of this thread. Unfortunately, that means you have to be somewhat clinical in analysis, and whilst your efforts are appreciated, the gathered evidence isn't up to drawing much by way of conclusions.

1) Not quite sure what you're trying to say there... if it's that we have different opinions, then I dispute that slightly, although I realise some may consider it a pedantic point. We have different theories as to what makes a good flashlight for use in fog, but ultimately only valid and scientific experimentation will yeild a difinitive answer.

2) I never said tint was the only affect, but introducing such a massive flaw into the experiment from the outset just makes any conclusions you draw open to massive interpretation. I am well aware that CRI is also a factor, but a cool white tinted LED will have a massively different CRI to a warm white tinted one anyway, so that just adds more credibility to disputing the comparison. There's actually enough of a difference in your beam shape there to also affect clarity, but the most noticable factor is the beam tint - I would say the incan actually has a dark spot in the centre, which may possibly mean that the target is illuminated more from scattered light than it is direct light. If you want to draw a conclusion as to a particular parameter, you need to reduce all the other factors to virtually zero - your two shots have quite a few differing factors, so you can't conclude it is down to one factor. We already know tint as well as beam shape makes a large different, so both need to be eliminated to refine the tests and further our understanding. Another factor which unfortunately is beyond control is the density of the fog... is there a way to measure that?

3) We need proper comparisons as a frame of reference, yes. Photographs with the camera on the same settings for both are a good start, providing the light sources are comparable. I have already stated why, in this case, the comparison lights aren't close enough in real world output to draw much of a conclusion.

4) I don't have enough light sources to do many comparisons, but I do have a camera with proper colour calibration setup from an industry recognised Kodac colour chart at all ISO and Shutter combinations with the different lenses I use. I also have access to a 'dark site' where there is virtually no light pollution present. I would be more than happy to do beamshots in cooperation with somebody who could provide flashlights. The biggest issue I would have is actually that we get very little fog in controlled conditions - it tends to be somewhat unpredictable! There seems little point in me posting beamshots of a common flashlight in commonly occuring conditions on this forum, there are already plenty if you use a search.

Dude, your assumptions are so absurd that even Baghdad Bob thinks you are full of fecal matter.

 

[Magic Matt]

Dude, your assumptions are so absurd that even Baghdad Bob thinks you are full of fecal matter.

There are ways to disagree with what I posted. Quoting it all then violating forum rule 4 probably isn't it. As a long term member, surely you know that?

If you think my statements are so absurd, then pleae by all means sensibly point out why. Don't flame me just because my reasoning doesn't fit with yours.

 

[Icebreak]

If you want to draw a conclusion as to a particular parameter, you need to

What you don't understand is that I'm not doing "the" experiment or "your" experiment. I don't need to do anything. I got up off the couch and did a beam shot comparison in the fog. I was there. I know what it looked like and it looked like the photo. In the real world. Where one gets dirt on one's boots.

- I would say the incan actually has a dark spot in the centre, which may possibly mean that the target is illuminated more from scattered light than it is direct light.

OK. I'll address this because it is interesting. There is no hole. That's an optical illusion. I know because I own the light. I know because I understand the illusion. Take my photos. Make a Gif. Extend the duration of the LED beam and the non-existent hole will appear greater on the incandescent beam.

If there was a hole in the beam, increasing the thresholds on the photo would detect it. It's simply not there. I can tell you that I've had these type discussions many times before and it's not uncommon for people to get a certain notion and no matter what you show them they won't change their minds. Often they'll find a fault in everything presented that opposes their notion. It's important to realize that and to respect....well I could go on but I won't.

 

[Magic Matt]

I got up off the couch and did a beam shot comparison in the fog. I was there. I know what it looked like and it looked like the photo. In the real world. Where one gets dirt on one's boots.

Perhaps there is some misunderstanding here due to differences in the way we use language - when I say "What you need to do" I don't mean you specifically, I mean anyone. It's a common use of phrase, particularly in southern England (UK) - I'll have to try and make sure I don't use that phrase in future.

My issue is that you seem, to me, to be using the shots as a way of saying that LEDs don't work as well as Incans - the beams are too different to draw that conclusion because, as I tried to point out originally, a blue incan may be as bad as the blue LED, and we know that warm LEDs perform better than blue ones. We know this from going outside when it's foggy and trying it.

Take my photos. Make a Gif. Extend the duration of the LED beam and the non-existent hole will appear greater on the incandescent beam.

You're right - there is no hole. What seems to be revealed is that the LED was directly on the back of the plant machinery, but the incan beam was significantly above it. I have observed on my walks that this makes quite a difference.

An interesting thing happens if you move the hotspot... I realise this is not particularly accurate way of doing things, but...

I can tell you that I've had these type discussions many times before and it's not uncommon for people to get a certain notion and no matter what you show them they won't change their minds.

I can assure you I am not one of those people. I'm not a fan of a particular technology over another. What I want to do is find the answer as to why some lights are better than others. I can't accept this...

This GIF may or may not serve to illustrate the distracting nature of the reflective light the fog returns to an LED source as opposed to how the fog reacts to a very similar incandescent source.

There are just too many other factors which explain why the shots are different over and above the type of emitter. What I originally thought to be a hole in the beam looks to be a different target position, slightly different in shape, and the colour tint is quite different. If the same test could be done by somebody using light sources that were much closer to each other, it would reveal more. They definately need to be much closer to begin with to draw any conclusion about whether it's down to using an LED over an incan.

 

[Icebreak]

Oh, great googley moogely, stop it Magic Matt. You're killing me over here.You photoshoped my photo and overylayed darkness on top of the equipment in the incan shot and now the powerline is going through the equipment. AWE SOME!

Again, I was there. As I've already described, the beams were aimed at the equipment. What you are seeing is where the reflection from the fog begins to stack up. It is less severe with the incan and begins sooner in the beam in what appears to be above the equipment due to perspective. This perspective is because the beam is generated from just above the camera. The reflectivity is not very heavy and this allows the rays, which can appear to be almost invisible in comparison to the visible beam, to hit the target causing a good image return. The fog reflection is more severe with the LED and stacks up later in the beam blocking the target.

Photoshopped darkness on top of my target...thanks for the laugh. :laughing:

 

[LuxLuthor]

I have the definitive answer on this question, after giving my US Navy lamp with the sealed GE 4546 bulb a good test since it had been previously suggested.

However, this thread has too many negative vibes going on to wade in now. What I want to know is who the heck is "Baghdad Bob" that O.F. mentioned? :wave:

 

[Icebreak]

Agreed.

In a more pleasant and mutually edifying direction here is some food for thought that should be somewhat palatable for all. This is not the first time words very similar to these have been posted:

Possibly the most important component of our flashlights and torches is the actual light that is thrust out of them. What that light does to illuminate its objective target in the way of returning an image to us is important enough to be the basis of many of our discussions. One of my favorite subjects to learn about is light itself. What creates it, how it acts and reacts, its intensity, its power and how it is defined are aspects of light that fascinate. Of great interest to me is the spectral components of a beam of light. The different frequencies or colors present in different light beam emissions can greatly effect the imagery or information returned to the user.


Here is a mildly entertaining, somewhat annoying "test". The answers are provided for ease of reading.

1) Environment: Fair to poor office lighting.

Would light from a blue LED peaking near 470 nm help or hinder in reading small print?

Answer:

It depends on the individual. Some people report that it blurs the print and hurts their eyes, some report there is not much difference, still others report a significant increase in their ability to read small print. One legally blind individual reported being able to retain their job which required reading small print simply by employing the use of a blue LED torch. He could not perform this function without the aid of blue Inova even with powerful glasses.

2) Environment: Low ambient lighting during a stage presentation such as a play.

Would light from red LEDs peaking near 625 nm spotting the target character help or hinder in defining the image of the target character?

Answer:

It depends on the individual. Some members of the audience will experience little effect in definition; others will notice a slight blurring; still others will notice some increase in definition. What most audience members will notice is a different definition rendition as well as a different depth rendition in comparison to everything else on the stage. These two differences highlight the target character and set that target character apart almost as much the obvious difference of the red color.

One individual reported that they were so visually impaired that they could barely navigate in low ambient light situations without the use of both a powerful blue light and a powerful red light used simultaneously. They designed and used a head mounted dual LED device to successfully satisfy this need.

3) Environment: Woods/Forest at night, clear sky, away from population and no moon.

Would light from a cyan LED peaking near 505 nm help or hinder vision in the area of defining the target image?

Answer:

It depends on the individual. Some individuals report that they lose so much color rendition that they feel almost bewildered. Others report a preference for cyan in this environment due to its definition of target capability as well as its particular color rendition capability. With effort, individuals can train their eyes/vision processing to take advantage of the aspects some wavelengths afford. 505 nm is one of those wavelengths.

4) Environment: Woods/Forest at night, clear sky, away from population and no moon.

Would light from a royal blue LED peaking near 455 nm help or hinder vision in the area of defining the target image?

Answer:

It depends on the individual. Some individuals report a blurring effect; others nothing; others reported that it was pretty. One individual reported that he could read distant signs he could not possibly read without royal blue light returning the image. Other individuals substantiated this report with their own real world investigations.

5) Environment: Jewelry store, low to no lighting.

Which frequency of light is best for causing diamonds to fluoresce?

Answer:

380 nm. 395nm will work also. However not all diamonds fluoresce. Some diamonds fluoresce different colors. If a yellowish diamond fluoresces blue, the effect could be strong enough to mask the yellowish tint when viewed in a jewelry store's fluorescent lighting. You might be surprised by the diamond's true color when you look at it at home under different lighting. The reverse is true for diamonds that fluoresce yellow. They can appear more white under incandescent lights, but acquire a yellowish tint in ultraviolet light. A strong yellow fluorescence bring diamond prices down, sometimes quite a bit, since yellowish tinted diamonds are generally less desirable than whiter stones. A blue fluorescence can help increase the prices of diamonds with yellowish tones.


6) Environment: Low ambient lighting during a stage presentation such as a play.

Which of these colors of light would be easiest to hide from the audience on non-target backgrounds; blue 470 nm, red 625 nm, cyan 505 nm or royal blue 455 nm?

Answer:

blue 470 nm.

7) Environment: Medical diagnosis.

Which color of light would be best for diagnosing subdermal vascular anomalies; blue 470 nm, red 625 nm, cyan 505 nm or royal blue 455 nm?

Answer:

red 625 nm. One specific instance is where 625nm/660nm is used in oximetry. 910nm IR is used in tandem in oximeters for attaining a ratio of absorption differential between the two (red and infrared) frequencies.


8) Environment: Woods/Forest at night, clear sky, away from population and no moon.

What color of light is best for tracking blood?

Answer:

The discussion continues among folks all over the world in many different venues. Some individuals report blue works for it’s absorption properties. Some individuals report that red works for its reflective properties. Some individuals report that a strong warm/white LED works very well while still others report that incandescent light is best for them.


9) Environment: World.

Which personal lighting tool is better for rendering diverse target images; LED or incandescent?

Answer:

It depends on the target and possibly more importantly it is dependent on the individual observer. All perspectives are valid.


Opinionated Commentary

Each individual has unique optical capabilities. Each individual has unique image processing capabilities. For a moment, couple all the above mentioned light frequencies and their different renditions of different targets with the fact that individuals see images differently. All those colors. All those targets. All those eyeballs. All those brains. One would think it would be a simple logical step forward to accept that one type of light is better for one person’s interpretation of a target image and a different type of light is better for another person’s interpretation of a target image. My observations indicate to me that it is in fact not such an easy logical step.

I think I may know why. It has to do with what is right before your eyes. We instinctively trust our vision for survival. What we see must be correct because we are seeing it. Now that might be considered to be empirical evidence. Add to that varying degrees of knowledge of light. From here the individual might submit that what works for them does so because of scientific fact. Since the preference is evidenced empirically and is supported by scientific fact, the preference might be considered to be an absolute. It’s not. It's their perception.

This is the complicated part of the pot of ingredients that can produce enthusiastic discussions and sometimes those discussions can cook up to produce quite a spicy dish of conversational fare.

And there’s more. One very interesting fellow has let me know (and I now agree with him) that people can train their eyes to use different types of light to enhance the information they receive from an image. Further he contends and I agree, that individuals can train their light processing capabilities and can even recalibrate their processors using different techniques not limited to but including simple concentration.

These words I’m using to attempt to make a point may or may not be of use. Let’s try another question. Is a blue LED the best choice for reading a map? Why, of course not. The best light for reading a map would be incandescent. No wait. The best light would be warmish white LED outputting exactly 28 lux. Maybe not. Remember that legally blind fellow who’s job depended on his ability to read small text and this task could only be accomplished by enhancing the target with a blue Inova? He doesn’t care what color the interstate is. He just wants to know where I-40 West is. Now if he and I were in a “save the world” scenario and he was the guy that had to cut the correct wire on the bomb before the timer reached zero, I might be inclined to hand him an incandescent light for its color rendition capability. A better choice for me, if time allowed, would be to ask him which light he would prefer for the task at hand. In this case his opinion makes a world of difference to me.

Like many, I have certain lighting preferences for different tasks.

While night fishing I prefer to use a tiny LED torch to tie lures, a no-spill TIR LED torch to spot the fish the guy twenty feet from me just pulled on shore and a powerful incan torch to see if that's a small branch or large snake floating in the water. Not everyone will prefer my choices. Individuals see images differently and process those images differently. If a fellow tells me he has no problem identifying an un-moving, mostly submerged cotton-mouth water moccasin at 30 feet out using an LED flashlight I’m inclined to believe his choice is best for him despite my own personal empirical evidence or my somewhat limited grasp of the science of light.

Is it possible that in a given environment and while targeting a given object, that one type of flashlight emitting a particular class of light beam might truly be more useful to some people while a different type of flashlight emitting a different class of light beam might truly be more useful to other people?

 

[Sub_Umbra]

That was one heck of a post, Icebreak. Lots of ground covered. I would add that many fail to realize the importance of an individual's ability to concentrate in any challenging visual situation like fog to mention just one.

In a group, concentration may take one person beyond his visual acuity alone. I've personally seen this happen over and over. Med students are often taught relaxation techniques to help them center themselves while sussing out subtle details when viewing x-rays.

The same is also true of hearing.

 

[Magic Matt]

Oh, great googley moogely, stop it Magic Matt. You're killing me over here.You photoshoped my photo and overylayed darkness on top of the equipment in the incan shot and now the powerline is going through the equipment. AWE SOME!

Glad I gave you a laugh - I was beginning to worry you were getting genuinely angry! LOL! I used the "light source shift" filter that came in a pack of 'Astronomy Tools'. I did say it wasn't a very good way of doing it. 🙂

What I was trying to point out is this....

This time I just did auto-levels ... quick way to find the hotspot basically.
Height A ... Height B ... it looks like the incan was pointing considerably higher and lighting the equipment with the spill, whereas the LED didn't have much spill so the main point of the beam was on the equipment.

You are sure it wasn't... ok - I have probably been inept at highlighting that, and I apologise for that, but I don't think anyone would argue that it's just not what it looks like in the photos.


Thank you for the massive post full of info - there's some great stuff there I will have a go at myself too.

I have the definitive answer on this question, after giving my US Navy lamp with the sealed GE 4546 bulb a good test since it had been previously suggested.

However, this thread has too many negative vibes going on to wade in now. What I want to know is who the heck is "Baghdad Bob" that O.F. mentioned? :wave:

Bagdad Bob was the Iraqi (dis)Information Minister in the most recent Iraq War. He was most famous for trying to insist they had the American infidels on the run from their troops, when the reality was very different. I think you can even get a DVD of his quotes - it's supposed to be quite funny. Of course there's a double negative there in that if Bagdad Bob thinks you're lying, you're probably telling the truth... 🙄

If I'm causing too many bad vibes then I most certainly apologise and I will stop posting in this thread. I wanted to take part in the debate and try to find the answers, not upset people. I will keep following the thread and not post again unless I'm invited to, as that would seem to be the best solution.


Please, LuxLuthor, post your information.

 

[Icebreak]

I would add that many fail to realize the importance of an individual's ability to concentrate in any challenging visual situation like fog to mention just one.

I've seen that happen also and agree that it's important to remember.

In a group, concentration may take one person beyond his visual acuity alone. I've personally seen this happen over and over. Med students are often taught relaxation techniques to help them center themselves while sussing out subtle details when viewing x-rays.

The same is also true of hearing.

I hadn't heard of this but it makes sense. Thanks for bringing that knowledge.

 

[Icebreak]

Maybe think of it like this, Magic Matt. You know that when you point a light into the sky you can see a beam. It's intensity has much to do with the atmosphere. But what you should have observed is that your light can illuminate past the visible beam. That's what you are seeing is the end of the visible beam as reflection stacks up as a return image. It appears to be the end of the visible but the angle takes the remaining illuminating rays straight to the target and causes a useful return image to be reflected back.

In the incan shot you have the fog being mildly reflected back but the target is nicely returning an image as the flashlight is pointed directly at it.