The Real Reason for Throw - an in depth examination

[Linger]

Re: The Real Reason for Throw-an in depth examination

Koti,

Your opinion may be entirely valid and it may be beneficial to have you explain it, however I caution that at this time it's just been an arguement. Maybe you could start a thread to expand on your ideas about surface brightness?
Saabluster asked for some time to flesh out some ideas in this thread: maybe he should have written it wholly before posting but that isn't required here and some constructive criticism was asked for. I feel your point has been stated: maybe hold off a few days until a fuller formed thesis has been posted. There will be lots of time for discussion after the stage is set.

 

[koti]

Re: The Real Reason for Throw-an in depth examination

I see Saabluster edited his original post so I hope Im not out of line speaking out...especialy that I did refrain from posting saying that I will wait. God knows why I refrained...I guess because common curtesy requires it. Funny that while I was "refraining" You two guys came in with posts.
What Saabluster wrote in his edited post is in my opinion not only fundamentaly wrong but he contradicts himself in 1 sentence:

"Surface brightness is not dependent on the area of the emitter but the saturation of light within the area. The use of area in respect to surface brightness is only to quantify what the actual relative surface brightness is"

First of all, its "density" not "saturation"
Secondly, photon density(or saturation if You realy want to call it that) is directly related to the area of the emitter.
More photon density = smaller emitter = higher surface brightness.

If You feel this is wrong, please take two surefire 6P's and put two different size diffusors on them. One regular P60 bezel size, the other the size of a basket ball. Put both lights in a dark field a mile away from Youreself and observe which one is brighter.
If what You are saying all along is right, they both should appear the same brightness. I assure You its not the case...just drive away from the lights...at some point You will loose the big diffusor light from your sight while the small diffusor light will still be visible. This is photon density, this is surface brightness.
I dont want to argue, really...but please now You refrain from further dissinformation untill You go thru Alisnails thread again and all the Ra's posts (this guy realy knows what hes talking about as opposed to both of us)

 

[saabluster]

Re: The Real Reason for Throw-an in depth examination

I see Saabluster edited his original post so I hope Im not out of line speaking out...especialy that I did refrain from posting saying that I will wait. God knows why I refrained...I guess because common curtesy requires it. Funny that while I was "refraining" You two guys came in with posts.
What Saabluster wrote in his edited post is in my opinion not only fundamentaly wrong but he contradicts himself in 1 sentence:



First of all, its "density" not "saturation"
Secondly, photon density(or saturation if You realy want to call it that) is directly related to the area of the emitter.
More photon density = smaller emitter = higher surface brightness.

If You feel this is wrong, please take two surefire 6P's and put two different size diffusors on them. One regular P60 bezel size, the other the size of a basket ball. Put both lights in a dark field a mile away from Youreself and observe which one is brighter.
If what You are saying all along is right, they both should appear the same brightness. I assure You its not the case...just drive away from the lights...at some point You will loose the big diffusor light from your sight while the small diffusor light will still be visible. This is photon density, this is surface brightness.
I dont want to argue, really...but please now You refrain from further dissinformation untill You go thru Alisnails thread again and all the Ra's posts (this guy realy knows what hes talking about as opposed to both of us)

You are going to kick yourself when it all finally "clicks". Please go read this page about luminance which is essentially what we are talking about.

Edit: I also see you chose to ignore my reading notes. Please review them again and adhere.

"Reading notes-The intent of this is to enlighten the CPF layperson and therefore strays away from uber technical terms such as luminance or the adherence to literal understandings of such words as throw. I use terms that are in common use here on CPF but the scientific principles that this "argument" is based on is intended to be sound. I do not wish to hear from those who are trying to be overly literal or picky in the minutia. If there is a fundamental flaw in the arguments presented here then please speak up."

Koti you keep making this way more complicated than it is. There is no need to add in all this talk about diffusers. We are talking about throw in this thread not flood. Adding a diffuser creates a new emitting surface. Here is the thing missing in your example. The collimating device that comes after it. I said it as clear as can be said with the muti-mode flashlight example.

 

[koti]

Re: The Real Reason for Throw-an in depth examination

You are going to kick yourself when it all finally "clicks". Please go read this page about luminance which is essentially what we are talking about.

I red it...it would be nice to add to that Wiki that Luminance is a measure of brightness on diffuse surfaces and its used for measuring brightness in device independent color profiles like CIE LAB for example (printer/monitor calibration color model...its a reference color model to calibrate devices and software)
As You can read in the last sentence of that Wiki :
"The light at the image plane, however, fills a larger solid angle so the luminance comes out to be the same assuming there is no loss at the lens. The image can never be "brighter" than the source."
I think that You are the one who needs to "click in" to see the light my friend...maybe another analogy will help :

You have two LCD monitors, both contain the same amount of pixels but one is a 15 inch monitor and the other is 20 inch. If You display the same image on both, which monitor will give You better quality ?
A hint...the smaller one. No aditional pixels (in our case its lumens), same amount of data - everything is the same exept for the size of the monitor (in our case emitter) is different.

Please try to think about my mind experiment with the two surefire 6P's with different size diffusors observed from a distance.

 

[Greg G]

Re: The Real Reason for Throw-an in depth examination

Koti, please allow the man to take the time to respond with a thoughtful post directed to us laymen.

Saabluster knows a lot, and we are lucky to have him in here interested in teaching us.

Thank you.

 

[saabluster]

Re: The Real Reason for Throw-an in depth examination

Koti you have expressly gone against my wishes in this thread. I respectfully request you refrain from any further posting here.

 

[koti]

Re: The Real Reason for Throw-an in depth examination

Im a man with a difficult piece of character so please excuse my frontness in a conversation.
Do think about those surefire 6P's with diffusers everyone :nana:

I will shut up now

Edit :
Oh boy...I just saw Saabluster add his post asking me not to post in this thread anymore.
What are we waiting for for the past 8 hours ?
Ive waited for You to finish editing your original post, I thought that this is the reason for no one to post (crazy if You ask me)
Seriously, this is just abstract...
I will not post for a few days in this thread though (although its just insane)

 

[Popsiclestix]

Re: The Real Reason for Throw-an in depth examination

A most excellent post so far saabluster, thank you for taking the time to provide information to help us keep everything clear.

However, I think the last sentence of this paragraph is a little misleading. Point sources of light by definition do not have any diameters. However, a non-perfect 80mm source of light in an infinitely large and perfect parabolic mirror will do as you describe.

Collimation in the truest sense of the word is not possible in the real world as it would require a point of light infinitely small. Assuming you did have the impossible point source of light, and this point was at the reflector or len's focal point, the resultant beam would never grow any larger than when it left the light. If I shone a light with a diameter of 80mm towards the moon there would be an 80mm beam of light on the moon.

 

[easilyled]

Re: The Real Reason for Throw-an in depth examination

I can't see where the confusion comes in.

Surface brightness mathematically is total brightness divided by the area of the die. I think of it like "brightness density".

An analogy I can think of is pressure which is force divided by area.

The pressure exerted by a stilleto heel would be much greater than that exerted by a shoe for the same weight of person.

To get the same pressure exerted by the shoe, the person would need to be about 30 times heavier, or whatever the ratio is between the area of the heel of the shoe compared to the area of the stilleto.

Anyway going back to light .....

The larger the die, the higher the total lumen output would need to be in order to provide the same surface brighness by compensating for the much larger area that the light is distributed over.

The SST-90 nearly succeeds in compensating for its 3*3mm squared die compared to the XR-E's 1*1mm squared die by outputting nearly nine times as much light at its maximum drive current as the XRE does at its maximum drive current.

Therefore I think its safe to say that at a surface brightness of 250 for the SST90 compared to the surface brightness of 270 for the XRE, that when both leds are pushed to their maximum drive currents, the XRE will throw a slightly greater portion of light down-range at the centre of the beam given that both dies are positioned at the correct focal length within a given optic.

This is only a small difference though (250 vs 270)

The SST-90 therefore still has a very respectable surface brightness when driven to 9A and when placed in a reflector that's large enough to collimate it with a tight beam (like in the Olight SR90), it "throws" very well indeed.

If an XRE were to replace the SST-90 in the same reflector of the Olight-SR90, it would "throw" slightly further but with a much narrower (and IMO less useful) beam.

That is my take on it anyway. Please feel free to correct any misconceptions that I have saabluster.

 

[koti]

Re: The Real Reason for Throw-an in depth examination

I can't see where the confusion comes in.

Surface brightness mathematically is total brightness divided by the area of the die. I think of it like "brightness density".

An analogy I can think of is pressure which is force divided by area.

The pressure exerted by a stilleto heel would be much greater than that exerted by a shoe for the same weight of person.

To get the same pressure exerted by the shoe, the person would need to be about 30 times heavier, or whatever the ratio is between the area of the heel of the shoe compared to the area of the stilleto.

Anyway going back to light .....

The larger the die, the higher the total lumen output would need to be in order to provide the same surface brighness by compensating for the much larger area that the light is distributed over.

The SST-90 nearly succeeds in compensating for its 3*3mm squared die compared to the XR-E's 1*1mm squared die by outputting nearly nine times as much light at its maximum drive current as the XRE does at its maximum drive current.

Therefore I think its safe to say that at a surface brightness of 250 for the SST90 compared to the surface brightness of 270 for the XRE, that when both leds are pushed to their maximum drive currents, the XRE will throw a slightly greater portion of light down-range at the centre of the beam given that both dies are positioned at the correct focal length within a given optic.

This is only a small difference though (250 vs 270)

The SST-90 therefore still has a very respectable surface brightness when driven to 9A and when placed in a reflector that's large enough to collimate it with a tight beam (like in the Olight SR90), it "throws" very well indeed.

If an XRE were to replace the SST-90 in the same reflector of the Olight-SR90, it would "throw" slightly further but with a much narrower (and IMO less useful) beam.

That is my take on it anyway. Please feel free to correct any misconceptions that I have saabluster.

I agree 100% with the above and I too dont understand where all the confusion is. Im glad to see that there is someone that has a clear view on this. Thank You for Your post easilyled.
I presume that Im going to be banned or at least blacklisted by Saabluster now that I spoke...after all, only certyain people are allowed to post in this thread

 

[Saint_Dogbert]

Re: The Real Reason for Throw-an in depth examination

A most excellent post so far saabluster, thank you for taking the time to provide information to help us keep everything clear.

However, I think the last sentence of this paragraph is a little misleading. Point sources of light by definition do not have any diameters. However, a non-perfect 80mm source of light in an infinitely large and perfect parabolic mirror will do as you describe.

Saabluster is not implying that a point source has a diameter. He means if you shone a light with an 80mm diameter reflector, containing a point-source of light, the resultant beam would have zero divergence and thus project a spot on the moon that was 80mm in diameter. This is of course ignoring the effects of the atmosphere. You are basically saying the same thing, but in a slightly more confusing way (to me at least).

 

[ejot]

Re: The Real Reason for Throw-an in depth examination

I too dont understand where all the confusion is.

Most of the confusion is coming from your posts. Especially the ones containing statment such as (emphasis mine):

"There is no such thing as just using brute force to overpower the weaker small die LED lights"
In my opinin [sic] the SR-90 does exactly that...it compensates for poor surface brightness with extreme emitter output and a well designed, huge reflector.

This is just nonsensical. Surface brightness is a function of emitter output and emitter area. There is no tradeoff or compensation between these quantities. What you may have meant, is that the extreme emitter output "compensates" for the large emitter area, resulting in a surface brightness comparable to smaller emitters with less output. This is clearly explained in both the original post and easilyled's post.

In fact, (the curiously indignant and petulant attitude aside), it is remarkable that you so strongly support easilyled's clarification of surface brightness while taking issue with the original post. They say the same thing. The first is a clear argument that perfectly matches the explanation with which you so emphatically just agreed.

The point in your many recent "examples" is absolutely true: Given two emitters with the same output and differing emitter areas, the emitter with the smaller area with have a higher surface brightness. No one is doubting that.

What your examples are completely neglecting, however, is equally relevant: Given two otherwise identical emitters with differing luminous flux output, the emitter with the greater output will have the greater surface brightness.

Or, said more simply, if you turn up the juice on one particular emitter, you increase its surface brightness.

Emitter size is not the ONLY determining factor in surface brightness. Just like volume is not the ONLY factor in determining mass density; you must also know the mass. Just like area is not the ONLY factor in determining pressure; you must also know the force.



The first part of the original post is accurate and well presented. There are a lot of people looking forward to the next updates and who would like to move forward with the discussion. I really hope that happens with the new page here.

 

[saabluster]

Re: The Real Reason for Throw-an in depth examination

A most excellent post so far saabluster, thank you for taking the time to provide information to help us keep everything clear.

However, I think the last sentence of this paragraph is a little misleading. Point sources of light by definition do not have any diameters. However, a non-perfect 80mm source of light in an infinitely large and perfect parabolic mirror will do as you describe.

Notice I was referring to a point source as it relates to an optical system. A point source light is not a collimated "beam". After the light passes through the optical system the rays are now parallel and will retain the same width as the collimating device.

That is my take on it anyway. Please feel free to correct any misconceptions that I have saabluster.

There are no major issues with what you said.:thumbsup:

 

[Steve'O]

Re: The Real Reason for Throw-an in depth examination

Koti.... forgive me for asking, but.... are you :drunk:

 

[easilyled]

Re: The Real Reason for Throw-an in depth examination

There are no major issues with what you said.:thumbsup:

No doubt there are minor ones though.

I do realize that my summary was an over-simplification, but my intention was to try to help corroborate what you have said with an explanation that laymen like me could identify with.

I would imagine that the fact that the SST-90 is a big die, makes the equation a bit more complicated because the photons emitted from the periphery of the SST-90 die are quite a long way from the centre and therefore when they are reflected, they go into a different part of the beam.
(probably accounting for why the hotspot is so much bigger for a larger die compared to a smaller one for a similar-sized optic)

They are also more out of focus because of the increased distance from the centre of the led compared with the XRE (for example) thus presumably making collimation less efficient and contributing to a reduction in "throw".

Also the lens of the SST-90 must also be a factor in affecting the beam-angle divergence of the light out of the SST-90. This is no doubt wider than the narrower angle of divergence from the XRE and it may be that the relatively shallow reflector of the Olight is more suitable for the wider divergence of light from the lens of the SST-90 than it would be for the narrower divergence from the lens of the XRE.

However, I'm sure you'll deal with all these issues and I'll find your explanation fascinating.

 

[DM51]

Re: The Real Reason for Throw-an in depth examination

A report has been submitted concerning koti's posts in this thread.

The topic saabluster is trying to explain is a very worthwhile; because it is a complicated one, he politely requested in post #1 that those who do not have a thorough understanding of it should refrain from commenting.

koti chose to disregard this, and in a total of 9 posts so far in this thread he has persisted in questioning saabluster's submissions. In each response he has made, saabluster has remained scrupulously civil and has repeatedly requested koti to refrain from making further posts in the thread.

There are 3 issues that could be said to have a bearing on the report concerning koti's posts.

The first concerns the relative merits of the arguments put forward by saabluster vs. those advanced by koti. I have read carefully through the thread; as background, I have also read numerous other related threads, including the Optic theory thread referred to in post #2; however in my view, the relative merits of the two arguments are not relevant to the complaint about koti's posts.

The second concerns whether or not an OP is entitled to ask another member to refrain from posting in his thread. This does not always apply but in this case, I feel saabluster was entitled to ask, and was also entitled to have his request respected.

The third is the matter of common courtesy and good manners. koti has clearly failed in this respect, and with his repeated refusal to respect the OP's wishes he has overstepped the line to the point where his contributions have become very disruptive.

So, koti… please stay out of this thread from now on.

 

[koti]

Re: The Real Reason for Throw-an in depth examination

A report has been submitted concerning koti's posts in this thread.

The topic saabluster is trying to explain is a very worthwhile; because it is a complicated one, he politely requested in post #1 that those who do not have a thorough understanding of it should refrain from commenting.

koti chose to disregard this, and in a total of 9 posts so far in this thread he has persisted in questioning saabluster's submissions. In each response he has made, saabluster has remained scrupulously civil and has repeatedly requested koti to refrain from making further posts in the thread.

There are 3 issues that could be said to have a bearing on the report concerning koti's posts.

The first concerns the relative merits of the arguments put forward by saabluster vs. those advanced by koti. I have read carefully through the thread; as background, I have also read numerous other related threads, including the Optic theory thread referred to in post #2; however in my view, the relative merits of the two arguments are not relevant to the complaint about koti's posts.

The second concerns whether or not an OP is entitled to ask another member to refrain from posting in his thread. This does not always apply but in this case, I feel saabluster was entitled to ask, and was also entitled to have his request respected.

The third is the matter of common courtesy and good manners. koti has clearly failed in this respect, and with his repeated refusal to respect the OP's wishes he has overstepped the line to the point where his contributions have become very disruptive.

So, koti… please stay out of this thread from now on.

I gladely will stay out of this thread (although I dont see a logical argument why I should) as I feel it brings more disinformation then usefuleness (at least in the surface brightness subject)
The whole thing with Saabluster posting a thread and asking everyone to shut up untill he says otherwise is abstract if not paranoia.
Im not the only one who writes in this thread, why dont You bann all the other people too?
I may have been a little disruptive, I appologize for that...but what Saabluster is doing is just overwhelmingly irritating.
I shall respect the Admin's DM51 decision and stop posting in this thread from now on.
Bravo Saabluster...You sure are the man with reporting me, thats some serious hero stuff.

Dm51..how can You post this :
"
The first concerns the relative merits of the arguments put forward by saabluster vs. those advanced by koti. I have read carefully through the thread; as background, I have also read numerous other related threads, including the Optic theory thread referred to in post #2; however in my view, the relative merits of the two arguments are not relevant to the complaint about koti's posts"

This is so unfair and so biased...how can You say that the relative merits of our arument are not relevant to the complaint against me?
Geezus, I happen to disagree with Saabluster's definition of how higher surface brightness can be achieved. I refrained from posting for many hours (God knows what were we waiting for at that time)
My arument was simple...smaller emitter - higher surface even though the lumen stay the same.
Please bann me from this post or this forum or whatever as Im not able to take this, sick...

 

[Benson]

Re: The Real Reason for Throw-an in depth examination

This is so unfair and so biased...how can You say that the relative merits of our arument are not relevant to the complaint against me?

Simple -- the complaint wasn't about you being wrong, it was about you posting despite saabluster's request that you not do so. However, I think it's rather safe to say that if disregard of your argument's merits does constitute an "unfair and so biased" approach, the bias is decidedly in your favor.

Please bann me from this post or this forum or whatever as Im not able to take this, sick...

Wait... you want banned?! I guess that explains much.

Well, I hope the mods can find a solution to this where everyone, including koti, gets what they want... :grouphug:

 

[koti]

Re: The Real Reason for Throw-an in depth examination

Simple -- the complaint wasn't about you being wrong, it was about you posting despite saabluster's request that you not do so. However, I think it's rather safe to say that if disregard of your argument's merits does constitute an "unfair and so biased" approach, the bias is decidedly in your favor.


Wait... you want banned?! I guess that explains much.

Well, I hope the mods can find a solution to this where everyone, including koti, gets what they want... :grouphug:

I have been asked to leave this thread and I shall do so.
Please do not adress me in this thread though. I think its unfair if Im only to watch and cannot reply.

 

[Mr. Tone]

Re: The Real Reason for Throw-an in depth examination

Thank you Saabluster, for this thread. At least to my layman status it is very clear, concise, and makes sense in the real world. I look forward to more from you on these matters. Hopefully, this thread can remain a source of good and solid info for CPF without being muddied up. Also thank you for your patience with others.