The Real Reason for Throw - an in depth examination

[JaguarDave-in-Oz]

I expanded by asking:

"Which light allowed them to best see the street sign down there [about a block away]?"
​

They all responded:

"That one! [the Barnburner]"
​

I'll let the group draw their own conclusions.

I conclude that I'm still in the dark over why "throw" cannot be just as well viewed as "distant object recognition"

 

[JaguarDave-in-Oz]

oh, and someone somewhere earlier complained that .25 lux was only as bright as moonlight. Well, on full moon nights down here I don't need a torch so .25 lux as a standard is just fine by me.

 

[wapkil]

2) I just want to be clear that I did not mention the NEMA 0.25 Lux figure, and can neither confirm or deny any such item. :green:

I'm sorry for the off topic post but I must say that I'm truly impressed by your ability to adhere to the copyright terms attached to the FL1 standard. It is especially worth mentioning in the context of the 0.25lx figure. I applaud your willingness to protect the confidentiality of this information. Especially since it was already published by multiple careless manufacturers, including the members of the NEMA Flashlight Standards Committee (Energizer, Streamlight, etc.).

I understand that standardizing bodies want to profit from their activity but I don't believe we should extend their rules to make the standards even more useless. It is bad enough that most consumers have no idea what the standards that are supposedly defined to protect them include.

 

[copperfox]

If "throw" is simply a measure of distant object recognition, then it's possible for lights with a floody beam to have throw. That means that in some cases, flood = throw. When words can be manipulated, they lose their meaning.

The term "throw" must take into account the beam pattern for this very reason.

 

[easilyled]

If "throw" is simply a measure of distant object recognition, then it's possible for lights with a floody beam to have throw. That means that in some cases, flood = throw. When words can be manipulated, they lose their meaning.

The term "throw" must take into account the beam pattern for this very reason.

We are defining our own (CPF's) term here as far as I understand.

Therefore if its not something that has already been defined, then its valid to have a difference of opinion about what the term means.

For practical purposes, however, if a light succeeds in illuminating an object at a certain distance away adequately, then to me it would "throw" adequately for the task in hand.

It wouldn't matter to me whether it was illuminating all the surrounds equally brightly or not.

In my opinion a light can have a "floody" beam distribution and still "throw" well too if it has enough surface brightness and overall flux to illuminate something at quite a distance away.

I see no conflict in this.

On the other hand, if a light is described as a "dedicated thrower", this suggests to me more that its beam pattern will be geared towards projecting a high proportion of its light forwards because this is its specific purpose.

For instance, I see the DEFT as a dedicated thrower and the SR90 Olight as having a more all-purpose beam that still "throws" very well.

 

[McGizmo]

If "throw" is simply a measure of distant object recognition, then it's possible for lights with a floody beam to have throw. That means that in some cases, flood = throw. When words can be manipulated, they lose their meaning.

The term "throw" must take into account the beam pattern for this very reason.

Well OK if you say so?

IMHO, the only reason to consider throw and design a light that will throw via a narrow beam is based on the consideration that a light source (incan bulb or LED) is insufficient in flux to provide illumination of a distant object without the use of a secondary optic which will condense and partially collimate its output. Granted the search lights that project their cool beams into the night sky to announce a grand opening or event are cool in their own right and recognizable by virtue of their beam shape. Most of us have enjoyed a flashlight sporting a similar beam shape as hand held light sabers in a hazy or foggy sky. In such cases, it is the beam itself we recognize and to see a sharp circle of light illuminating a distant target is also really cool.

On the train of thought I am attempting to express here, I find myself comfortable with the subject title of the real reason for throw. I would say the real reason for throw is to illuminate distant objects sufficiently. Would you counter that the real reason for throw is to provide a recognizable beam of obvious intensity and narrow beam angle? A throw light is one of tight beam angle and a flood light is one of wide beam angle? In fixed lighting these two types of light sources are are identified as spot lights and flood lights. IMHO, throw is about distance and not beam angle. The confusion arises because throw will always be increased by increasing the concentration or collimation of a given light source and consequently we witness a narrowing of beam angle as we increase the throw of a specific light source.

You equate flood=throw and clearly this makes no sense. For a given light source and any secondary or multiple optic management of its output, the tighter its beam angle holding constant transmission of flux, the greater it throw. Flood is an understood function of wide beam dispersion and spot is understood as a function of narrow beam dispersion. These are terms of beam shape and a good flood or a good spot is likely to mean that you have clean and effective illumination based on their specific application.

 

[saabluster]

Well OK if you say so?

IMHO, the only reason to consider throw and design a light that will throw via a narrow beam is based on the consideration that a light source (incan bulb or LED) is insufficient in flux to provide illumination of a distant object without the use of a secondary optic which will condense and partially collimate its output. Granted the search lights that project their cool beams into the night sky to announce a grand opening or event are cool in their own right and recognizable by virtue of their beam shape. Most of us have enjoyed a flashlight sporting a similar beam shape as hand held light sabers in a hazy or foggy sky. In such cases, it is the beam itself we recognize and to see a sharp circle of light illuminating a distant target is also really cool.

On the train of thought I am attempting to express here, I find myself comfortable with the subject title of the real reason for throw. I would say the real reason for throw is to illuminate distant objects sufficiently. Would you counter that the real reason for throw is to provide a recognizable beam of obvious intensity and narrow beam angle? A throw light is one of tight beam angle and a flood light is one of wide beam angle? In fixed lighting these two types of light sources are are identified as spot lights and flood lights. IMHO, throw is about distance and not beam angle. The confusion arises because throw will always be increased by increasing the concentration or collimation of a given light source and consequently we witness a narrowing of beam angle as we increase the throw of a specific light source.

You equate flood=throw and clearly this makes no sense. For a given light source and any secondary or multiple optic management of its output, the tighter its beam angle holding constant transmission of flux, the greater it throw. Flood is an understood function of wide beam dispersion and spot is understood as a function of narrow beam dispersion. These are terms of beam shape and a good flood or a good spot is likely to mean that you have clean and effective illumination based on their specific application.

I'm Michael and I approve this message.:thumbsup:

 

[dymonite69]

Copperfox seems to be the main proponent of a beam-pattern based versus illumination-based definition for 'throw'. The former 'unfairly' advantages a light source with crude optics but high lumens output to provide better range than one with modest output but superbly crafted and elegantly designed optics.

In most cases if a person chooses a 'bright' light they will choose the one with the greatest useful range without much consideration about beam angle.

Of course there may be tactical advantages of a narrow beam. An example is where one wishes to use it as a signaling device or achieve focussed illumination without detection by others outside of the path of the beam (giving away a position).

Perhaps Copperfox's appeal is that this quality be recognised. Whether this is falls under the term 'throw' or represents a separate definition is a matter of discussion.

 

[copperfox]

Stop ganging up on me! :tinfoil:

Well OK if you say so?

IMHO, the only reason to consider throw and design a light that will throw via a narrow beam is based on the consideration that a light source (incan bulb or LED) is insufficient in flux to provide illumination of a distant object without the use of a secondary optic which will condense and partially collimate its output.

Yes, in the real world we are more often constrained by flux than by factors that affect beam pattern (it won't be anybody's EDC, but you can make a reflector 4 inches wide). But if we are trying to create a definition of throw, we cannot only consider today's limited technology.

...Would you counter that the real reason for throw is to provide a recognizable beam of obvious intensity and narrow beam angle? A throw light is one of tight beam angle and a flood light is one of wide beam angle? In fixed lighting these two types of light sources are are identified as spot lights and flood lights. IMHO, throw is about distance and not beam angle. The confusion arises because throw will always be increased by increasing the concentration or collimation of a given light source and consequently we witness a narrowing of beam angle as we increase the throw of a specific light source.

Yeah.

You equate flood=throw and clearly this makes no sense. For a given light source and any secondary or multiple optic management of its output, the tighter its beam angle holding constant transmission of flux, the greater it throw. Flood is an understood function of wide beam dispersion and spot is understood as a function of narrow beam dispersion. These are terms of beam shape and a good flood or a good spot is likely to mean that you have clean and effective illumination based on their specific application.

No, I think you misunderstood me. I'm not equating throw and flood. I'm warning that we cannot equate the two. What I'm saying is that the reason we cannot equate throw with lux on a target is because a floody beam can, in some cases, put more lux on that target (it just has to be substantially brighter) than the throwy beam. Therefore LUX =/= THROW.

Copperfox seems to be the main proponent of a beam-pattern based versus illumination-based definition for 'throw'. The former 'unfairly' advantages a light source with crude optics but high lumens output to provide better range than one with modest output but superbly crafted and elegantly designed optics.

In most cases if a person chooses a 'bright' light they will choose the one with the greatest useful range without much consideration about beam angle.

Me too. Like I said before, throw doesn't necessarily mean useful. Give me a Mag85 over a DBS anyday (runtime notwithstanding). It may not be as throwy as the DBS, but it makes up for it with brightness.

 

[gcbryan]

LuxLuthor the only comment I have regarding your experiment with your neighbors is would their conclusions change if the light was shining at the street sign two blocks away?

I guess the question then becomes how far can the human eye realistically see and recognize something and then that of course depends on the size of the object.

So for a street sign one block is probably about the useful limit. For a building it would be quite a bit further and therefore which of your lights that was considered to throw the furthest might change.

 

[dymonite69]

I guess the question then becomes how far can the human eye realistically see and recognize something and then that of course depends on the size of the object.

and how brightly

Read this Wackipedia summary of visual acuity:

http://en.wikipedia.org/wiki/Visual_acuity#Physiology_of_visual_acuity

In bright light we can discriminate between two objects separated by a visual angle of 30 arcseconds or 1/120th of a degree.

In dim light maybe only half a degree (a 60x difference)

Normal on the Snellen eye chart is considered 5 arcminutes under 480 lux. It is equivalent to a 88.7mm high letter viewed at 60 metres.

NB

360 degrees in a circle
60 arcminutes in a degree
50 arcseconds in a minute

 

[JaguarDave-in-Oz]

No, I think you misunderstood me. I'm not equating throw and flood. I'm warning that we cannot equate the two. What I'm saying is that the reason we cannot equate throw with lux on a target is because a floody beam can, in some cases, put more lux on that target (it just has to be substantially brighter) than the throwy beam. Therefore LUX =/= THROW.

"That flood light can throw light a suprisingly long way" "it has quite good throw for a flood light"

I'm comfortable with the two together.

 

[mudman cj]

What I'm saying is that the reason we cannot equate throw with lux on a target is because a floody beam can, in some cases, put more lux on that target (it just has to be substantially brighter) than the throwy beam. Therefore LUX =/= THROW.

Where you said the floody beam has to 'put more lux on that target' I think you meant to say it has to put more total flux on that target. In other words, the peak light intensity, or lux, may be less important than the total number of photons hitting the target. I'm just trying to clarify for other members that may benefit, not pick on you.

 

[kengps]

I think what he means is that a "floody" light can equal the same amount of lux on a target as a "throwy" light...But it takes much more "lumen" to equal a "throwy" light, because it applies equal lux to a much larger spot area.

 

[kengps]

Here's another subject I want to know about.....Multiple head lights. There are a number of lights out there with 3 or more heads all aligned the same. (same effect shining 2 or more flashlights on the same target) Does the total lux simply multiply by the number of light sources? If so...would for example 3 heads give you 1.73 times the throw distance of a single light?

 

[McGizmo]

Copperfox

Therefore LUX =/= THROW.

Did you mean to type Flux =/= Throw?

If you are attempting to state that throw is independent of Lux then you really have me confused?!?!

 

[Benson]

@Copperfox:
You say, basically, that throw can't be defined by looking only at beam-center/peak intensity, because then a naked arc light (or any other high-power source) providing a very floody beam could have more throw than a tightly collimated light with a narrow spot.

I'd like to suggest an analogy. Consider weight. Is it right to say that the "heaviness" of an object can't be measured only in terms of its weight, because then feathers (by the truckload) would be "heavier" than lead (by the spoonful)?

Of course not -- in this case, I think it's clear that the feathers/lead comparison illustrates not that either definition is wrong, but that we need two related terms to cover the related concepts of total weight and per-volume weight: weight and density. (Unfortunately, the actual term "heavy" still remains quite ambiguous in common usage. )

Similarly, I think that we can use two terms:

• Throw: a monotonic function of beam-center (and/or peak, for things like quad-dies with projected donut-holes) intensity. Something like the second or fourth root (times an appropriate constant) can give relatively meaningful measures of a distance the beam is expected to be useful at, but the exact choice of function is non-critical, as long as it's clearly expressed. You can always back out to luminous intensity and convert to your own favored scale.
• Throwiness: A measure of concentration of the beam. I'd be content with the peak intensity (in cd) divided by the total flux (in lm), but this is much more complicated to agree on a definition.

While I'm not real happy with the noun->adjective->noun formation of throwiness, we need a term for each of these concepts, and I think the throw/throwiness pair comes as close as any definitions can to prevailing usage on CPF. As witnessed by everyone piling on you, at least your usage of throw for what I've called throwiness does not seem to match consensus, at least among the posters in this thread.

Under this set of definitions, while a MW arc light might have more throw than a DEFT, and would be said to outthrow the DEFT, the DEFT would have much more throwiness.


@kengps: yes, provided the heads are all aligned properly.

 

[LuxLuthor]

Everyone should keep going after Copperfox, as there always needs to be a protagonist in any drama! In fact, I have it on good authority that his mom wears army boots made in a Vietamese sweat shop!

Actually, it is quite useful when people raise their "yeah, but's" in terms of testing a hypothesis. If it can't be defended as new thoughts/challenges are raised, then it needs improvement/refinement. I raise a flag of caution on Michael making comments of approval or disapproval--in effect being the final arbiter, since it is his proposal we are examining. For it to be valid for the community, it needs to make sense to the community. So far, Michael's definition of "Throw" has not crossed that bridge for me personally.

My example with the 3 guys illustrated that "throw" is a CPF made up term. As such, there remain many interpretations as to what it means, because there has not been an open & rigorous discussion like this before. This thread, and what you are seeing as responses are how a consensus is built.

Throw- A concentrated beam of light that reaches or exceeds the lower threshold of human vision to see a distant target with clarity relative to the user and intended target.
​

I cannot dismiss the reality that the relatively poorly concentrated Barnburner or 100W Maglite mods (i.e. Mac's 64623 "The Torch") in many cases provide excellent visualization of a far target, even if there is also significant spill and corona around the spot. Obviously these have a sufficiently "concentrated beam of light" to satisfy the above description, but I'm not sure I would consider "The Torch" with it's MOP (highly textured, medium orange peel) reflector to be a "Throwing Light."

I am reminded of the reflector shootout I did in this thread, and specifically of this rotating gif image showing the results of a Mag85 with 7 different reflector texture coatings shining on a carriage house 50 yards away.

My difficulty is with the qualification "concentrated" which could mean lots of things to lots of people. I think there needs to be a decision made on whether you want the entire beam to be concentrated (confined output angle) like the MaxaBeam or DEFT, or if the center hotspot of a light also qualifies as being sufficiently concentrated to satisfy being a far throwing light. I can say that in general, CPF members use the term "a throwing light" in various shootouts when describing the far illumination target by the light's center hotspot.

In other words, if the "meat" of Michaels's 'Throw' definition is defined by "seeing a distant target with clarity," then I would suggest that the beam does not necessarily need to be "concentrated." I think there needs to be additional terminology/refinement/qualifications addressing my examples of brute force lights (Barnburner/The Torch) in any definition of throw.

 

[kengps]

I don't think introducing concentration does anything for defining what throw is. Seems to be introducing a variable (or preference) that has nothing to do with throw. Two lights that could illuminate a target at equal distant could have the same "Throw" Yet one could be a flood with a gazzillion Lumens, and the other light with equal "throw" could be a 300 lumen spot beam like a Deft. All that matters in defining "throw" is how much Lux is on the target.

 

[dymonite69]

Here's another subject I want to know about.....Multiple head lights. There are a number of lights out there with 3 or more heads all aligned the same. (same effect shining 2 or more flashlights on the same target) Does the total lux simply multiply by the number of light sources? If so...would for example 3 heads give you 1.73 times the throw distance of a single light?

If centre of beam of each light source are all focussed on the same spot then you will get three times the intensity. But not at any another range.