This is about flashlight design from a user perspective. The subject flashlight is an every day carry light (EDC light) that serves a security and utility function. I'll state what I require from an EDC light. But, what I am trying to do is not just give a list of requirements but also give why I require them and how I reached that decision.
I'm not trying to establish the way all flashlights should be. Each person has different needs and their requirements will vary. I'm not trying to say all ECD light should be designed to the specification I'll list below. I'm discussing the logic behind what I require and the approach for the makers to reach that requirement.
The Beam
I need the beam to have enough intensity to let me see objects out to at least 100m, and preferably up to 200m. I can't be against the beam having enough width for me to see the surroundings of the object I want to see. But, the problem is that since the subject is a hand held light small enough for EDC, there just isn't enough power to have both throw and flood quality. That means I'll have to choose between focused beam that reaches far (throw) or wider width beam (flood) that does not reach as far.
Each has its place, but I'll have to choose throw over flood. The reason is that many things I might need a light for calls for focused intensity. Also, I can see objects out side of the beam by either scanning or by indirect illumination with a long throw beam. I can't see objects at a distance with a flood beam no matter what I do.
I need to identify things that can be a threat as far as possible. More intensity is required for me to identify objects than just light up an area. If I need to see through a glass, tinted glass, a clutter such as bushes, I need more intensity. In a situation where you have to navigate through a dark area, being able to see down an entire city block or 100m beyond radius makes situational awareness significantly better then only being able to see up to where you'll walk into in a few seconds.
For the same reason, I prefer the light to be bright as possible, somewhere in the range of 200~300 lumen with a tightly focused beam. Some consider this to be too bright, but I disagree. If the light's sole expected use is indoors or close range, then they do have a point. But, otherwise, any light that does not meet my requirements will present some operational problems. It is uncomfortable to stare right in to a bright spot of a 200+ lumen light beam projected on a wall right in front of you than doing the same thing with a 60~150 lumen light. But, that's not the way it's normally used. And, even when I did it, it did not "blind" me as some said it would. Sure, it's bad for the night vision, but for someone to talk about preserving night vision while lighting up objetcts with 60+ lumen light and say it's better preserve night vision than a 200+ lumen light is a joke. seriously...(Akin to someone talking about "element of surprise" dynamic entry on a seond room when the team threw a flash bang or grenade when they entered the first room.)
So, exactly how much light is needed? Let's examine some situations.
One example: Where a police officer approaches a car.
Let's say the suspect car is stopped about 10m away. If this is a regular traffic stop, the spot light from the police vehicle may help, but in this situation the officer is away from any police vehicle. In total darkness, a 60 lumen light may provide enough light to identify the vehicle, license plate, etc. Want to view how many is inside? More light may be needed. Want to view what each individual is doing? Identify what is in their hands? More light. What if the window is lightly tinted? Even more light.
What about ambient light? Ambient light only helps about half the time. What about the other situations? It either does not help or actually work against you. There can be many dynamic and static light sources in your area, illuminating different points in different degrees. Your light may need more power to overpower the ambient light if it's working against you on top of the power level you needed in total darkness.
Another example: Focused intensity is also important when the light is used to illuminate a target for a firearm. This is especially true with iron sights. More light is needed to visually recognize and track the target while the eye is focused on the front sight of the firearm. If you can only barely recognize something at certain distance with a certain light, the range you can use the iron sight to aim the target would be significantly shorter. Optics where the target image and the reticle appear at the same range can reduce this problem. Both the reticle and the target would appear focused, even if the target is dimly lit, but it won't appear as bright as not looking through an optic. Only exception may be a magnified optic that collects light.
When all these are put into consideration, you might find yourself quickly becoming more and more power hungry in level of power you require from your light.
Interface
The flash light must have the following basic modes:
-Momentary activation in max brightness
-Constant on/off in max brightness
-Med~low brightness mode that gives me a run time of 10~20 hrs. Momentary and constant mode.
This is a EDC light that may be used as security purpose. So, the most important thing for the
light interface is to give me immediate access to momentary activation mode without any hindrance. I should not have to switch mode or do any additional action to get to it. And, I should be able to get to it through a tail switch with nothing obstructing the use of the switch with any type of grip I might have to use. Obviously, obstructions such as a tail stand tail cap would be a no go, this is NOT a candle.
This means no matter how I press the switch in what pattern, the light must stay in momentary mode unless I make a deliberate attempt to change it to a different mode. This disqualifies all flashlights what switches mode by switch press pattern because if the pattern I press the switch happens to match the preprogrammed pattern for mode switch, the light would change mode without me intending to do so.
This also means the resistance of the tail switch has to be tuned fine. If it's too hard, it's hard to activate the switch in a Rogers/Surefire grip. If it's too soft, then the light can come on too easily on contact when the user does not intent to turn it on.
Setting the details of med~low brightness mode requirements was tricky for me. I used to run security light and utility light separately. The utility light had a longer run time requirement because I planned to use it in a situation where I have to operate in darkness for long time when no other light is available. I find 20~30 lumen range to be workable to read or manipulate things close by and see what is near by to find my way when I don't need to see far. 60+ lumen mode is even better for some things, but it's stressful for the eye to read something when I put the beam that bright on a paper in front of me. Today, instead of security light and utility light, I run two flashlights that serve both function. The reason is that I require I always have a security light with full charged batteries, and since I'm draining battery power for utility use I need another light on stand by.
If you had to navigate through mid town Los Angeles during power out, and you're using a pocket flashlight with god knows how much battery power is left to navigate through it, you'll recognize how much relief it is to have a second light with fresh batteries on you. And, I can think of many reasons why I don't want to fumble with the flashlight trying to change batteries in total darkness.
I decided that 20~30 lumen is optimal for low mode, and if I need more brightness, then the max brightness mode will do. If I have 20~30 lumen, max, and another mode between the two brightness, it would be better, which most lights do these days. But, if I have to choose only two then it would be max and 20~30 lumen mode.
The low mode is also useful in security aspect. I can inspect my immediate surrounding area such as a small yard, without announcing yourself to the whole world. Of course, this is not "stealthy" and anyone who has a direct line of sight to you would see the light. But, it would not lit the whole area or room up as if you flipped the light switch on as more brighter level light would. And, in city situation where there's a lot of ambient light, it would go unnoticed by most people who are not particularly looking out for you.
For the flashlight in this discussion, I would like to have quick access to two primary brightness mode: Max and low. Having multiple modes as sub modes does not hurt, but that is true only if it does not hinder my access to the basic modes. And, if that means more step is necessary to access the sub modes, then so be it.
Each light has its limitations. If you require these small pocket lights to be everything, then it won't be quite good at anything. My primary focus is that this light serve all the basic functions of a security light and serve some utility light functions. I don't need strobe, I don't require multiple color, I don't require 10 different brightness mode, etc. There are situations where I might find those fancy modes other than momentary high and low useful, but in those kind of situations I would have a dedicated multi mode utility light. I live in a big city. And, if I find my self where I might need a strobe light, such as recreational activities in mountains, I'd have a dedicated multi mode utility light in addition to my EDC light, and probably a real strobe on top of it. And, I do keep a Streamlight Sidewinder near by, although not on my person.
I've used a bunch of flashlights, and let's take a look at some interfaces.
One of them I liked was Surefire L1. This one does not meet my beam strength requirement, but I liked the interface. Simple, and gives quick access to low and high mode. For a simple two mode light for my purpose, it's quite effective.
Another one I liked was Inova Inforce. It's a bit more complicated than something like L1, but fairly straight forward. Just twist the selector to the mode you want and use the tail switch. No tapping around the switch, multiple tight and loosen motion, etc. involved. Inova did make a critical mistake with the "combat strobe" mode. For some reason, they made it a constant on/off. I can see where constant on/off may be useful, but since it's a "combat strobe" not giving a momentary activation option is a mistake.
EagleTac P100C2 is a good light too. The interface is very simple and acceptable. 4Seven's Quark 123^2 Tactical interface is almost identical if you only use the two primary modes and ignore the sub modes. I say it's acceptable because I don't like the twist tighten and loosen motion. I feel as if repeat use of that motion would cause wear and I don't want the bezel to become loose. This is also the reason why I advocate the max brightness setting is at the "tightened" position when this type of interface is used. So, I can tighten it and leave it there unless there is a specific need for a low mode. If the worn bezel won't maintain position in low mode, it would be less risk for me than the bezel drifting in high mode when I need it. And, it will more likely maintain position in tightened position.
One that I dreaded was the Surefire Outdoors Man. If I accidentally double tap it, then it would not say on low. I can't get an immediate high mode. Not particularly good at anything. What were they thinking?
LED vs. Incandescent
For me, it's LED. It's for a very simple reason. I don't want to rely on an equipment that its life is numbered by the days, especially when it's on daily use. I don't keep log of how long I used the bulb, and I'm not aware of a single "operator", soldier, police officer who does. Incandescent bulb will burn out. I have no way of telling when that's going to be, but since I do use the light frequently it will happen in the near future if I use incandescent. That means I have to carry a spare bulb, which is not cheap, if I use incandescent. And, there is no tangible operational benefit what so ever for me to use incandescent over LED. I'll go as far as to say for someone whose life may depend on a working light to use incandescent without carrying a spare bulb, especially when the light is regularly used, might be out of their mind. Years ago, when first Surefire line of LED came out that matched the power of 6P, I switched to Surefire LED even though it cost almost twice. L4 had only about 65 lumen back then, if I recall correctly.
I'm not trying to establish the way all flashlights should be. Each person has different needs and their requirements will vary. I'm not trying to say all ECD light should be designed to the specification I'll list below. I'm discussing the logic behind what I require and the approach for the makers to reach that requirement.
The Beam
I need the beam to have enough intensity to let me see objects out to at least 100m, and preferably up to 200m. I can't be against the beam having enough width for me to see the surroundings of the object I want to see. But, the problem is that since the subject is a hand held light small enough for EDC, there just isn't enough power to have both throw and flood quality. That means I'll have to choose between focused beam that reaches far (throw) or wider width beam (flood) that does not reach as far.
Each has its place, but I'll have to choose throw over flood. The reason is that many things I might need a light for calls for focused intensity. Also, I can see objects out side of the beam by either scanning or by indirect illumination with a long throw beam. I can't see objects at a distance with a flood beam no matter what I do.
I need to identify things that can be a threat as far as possible. More intensity is required for me to identify objects than just light up an area. If I need to see through a glass, tinted glass, a clutter such as bushes, I need more intensity. In a situation where you have to navigate through a dark area, being able to see down an entire city block or 100m beyond radius makes situational awareness significantly better then only being able to see up to where you'll walk into in a few seconds.
For the same reason, I prefer the light to be bright as possible, somewhere in the range of 200~300 lumen with a tightly focused beam. Some consider this to be too bright, but I disagree. If the light's sole expected use is indoors or close range, then they do have a point. But, otherwise, any light that does not meet my requirements will present some operational problems. It is uncomfortable to stare right in to a bright spot of a 200+ lumen light beam projected on a wall right in front of you than doing the same thing with a 60~150 lumen light. But, that's not the way it's normally used. And, even when I did it, it did not "blind" me as some said it would. Sure, it's bad for the night vision, but for someone to talk about preserving night vision while lighting up objetcts with 60+ lumen light and say it's better preserve night vision than a 200+ lumen light is a joke. seriously...(Akin to someone talking about "element of surprise" dynamic entry on a seond room when the team threw a flash bang or grenade when they entered the first room.)
So, exactly how much light is needed? Let's examine some situations.
One example: Where a police officer approaches a car.
Let's say the suspect car is stopped about 10m away. If this is a regular traffic stop, the spot light from the police vehicle may help, but in this situation the officer is away from any police vehicle. In total darkness, a 60 lumen light may provide enough light to identify the vehicle, license plate, etc. Want to view how many is inside? More light may be needed. Want to view what each individual is doing? Identify what is in their hands? More light. What if the window is lightly tinted? Even more light.
What about ambient light? Ambient light only helps about half the time. What about the other situations? It either does not help or actually work against you. There can be many dynamic and static light sources in your area, illuminating different points in different degrees. Your light may need more power to overpower the ambient light if it's working against you on top of the power level you needed in total darkness.
Another example: Focused intensity is also important when the light is used to illuminate a target for a firearm. This is especially true with iron sights. More light is needed to visually recognize and track the target while the eye is focused on the front sight of the firearm. If you can only barely recognize something at certain distance with a certain light, the range you can use the iron sight to aim the target would be significantly shorter. Optics where the target image and the reticle appear at the same range can reduce this problem. Both the reticle and the target would appear focused, even if the target is dimly lit, but it won't appear as bright as not looking through an optic. Only exception may be a magnified optic that collects light.
When all these are put into consideration, you might find yourself quickly becoming more and more power hungry in level of power you require from your light.
Interface
The flash light must have the following basic modes:
-Momentary activation in max brightness
-Constant on/off in max brightness
-Med~low brightness mode that gives me a run time of 10~20 hrs. Momentary and constant mode.
This is a EDC light that may be used as security purpose. So, the most important thing for the
light interface is to give me immediate access to momentary activation mode without any hindrance. I should not have to switch mode or do any additional action to get to it. And, I should be able to get to it through a tail switch with nothing obstructing the use of the switch with any type of grip I might have to use. Obviously, obstructions such as a tail stand tail cap would be a no go, this is NOT a candle.
This means no matter how I press the switch in what pattern, the light must stay in momentary mode unless I make a deliberate attempt to change it to a different mode. This disqualifies all flashlights what switches mode by switch press pattern because if the pattern I press the switch happens to match the preprogrammed pattern for mode switch, the light would change mode without me intending to do so.
This also means the resistance of the tail switch has to be tuned fine. If it's too hard, it's hard to activate the switch in a Rogers/Surefire grip. If it's too soft, then the light can come on too easily on contact when the user does not intent to turn it on.
Setting the details of med~low brightness mode requirements was tricky for me. I used to run security light and utility light separately. The utility light had a longer run time requirement because I planned to use it in a situation where I have to operate in darkness for long time when no other light is available. I find 20~30 lumen range to be workable to read or manipulate things close by and see what is near by to find my way when I don't need to see far. 60+ lumen mode is even better for some things, but it's stressful for the eye to read something when I put the beam that bright on a paper in front of me. Today, instead of security light and utility light, I run two flashlights that serve both function. The reason is that I require I always have a security light with full charged batteries, and since I'm draining battery power for utility use I need another light on stand by.
If you had to navigate through mid town Los Angeles during power out, and you're using a pocket flashlight with god knows how much battery power is left to navigate through it, you'll recognize how much relief it is to have a second light with fresh batteries on you. And, I can think of many reasons why I don't want to fumble with the flashlight trying to change batteries in total darkness.
I decided that 20~30 lumen is optimal for low mode, and if I need more brightness, then the max brightness mode will do. If I have 20~30 lumen, max, and another mode between the two brightness, it would be better, which most lights do these days. But, if I have to choose only two then it would be max and 20~30 lumen mode.
The low mode is also useful in security aspect. I can inspect my immediate surrounding area such as a small yard, without announcing yourself to the whole world. Of course, this is not "stealthy" and anyone who has a direct line of sight to you would see the light. But, it would not lit the whole area or room up as if you flipped the light switch on as more brighter level light would. And, in city situation where there's a lot of ambient light, it would go unnoticed by most people who are not particularly looking out for you.
For the flashlight in this discussion, I would like to have quick access to two primary brightness mode: Max and low. Having multiple modes as sub modes does not hurt, but that is true only if it does not hinder my access to the basic modes. And, if that means more step is necessary to access the sub modes, then so be it.
Each light has its limitations. If you require these small pocket lights to be everything, then it won't be quite good at anything. My primary focus is that this light serve all the basic functions of a security light and serve some utility light functions. I don't need strobe, I don't require multiple color, I don't require 10 different brightness mode, etc. There are situations where I might find those fancy modes other than momentary high and low useful, but in those kind of situations I would have a dedicated multi mode utility light. I live in a big city. And, if I find my self where I might need a strobe light, such as recreational activities in mountains, I'd have a dedicated multi mode utility light in addition to my EDC light, and probably a real strobe on top of it. And, I do keep a Streamlight Sidewinder near by, although not on my person.
I've used a bunch of flashlights, and let's take a look at some interfaces.
One of them I liked was Surefire L1. This one does not meet my beam strength requirement, but I liked the interface. Simple, and gives quick access to low and high mode. For a simple two mode light for my purpose, it's quite effective.
Another one I liked was Inova Inforce. It's a bit more complicated than something like L1, but fairly straight forward. Just twist the selector to the mode you want and use the tail switch. No tapping around the switch, multiple tight and loosen motion, etc. involved. Inova did make a critical mistake with the "combat strobe" mode. For some reason, they made it a constant on/off. I can see where constant on/off may be useful, but since it's a "combat strobe" not giving a momentary activation option is a mistake.
EagleTac P100C2 is a good light too. The interface is very simple and acceptable. 4Seven's Quark 123^2 Tactical interface is almost identical if you only use the two primary modes and ignore the sub modes. I say it's acceptable because I don't like the twist tighten and loosen motion. I feel as if repeat use of that motion would cause wear and I don't want the bezel to become loose. This is also the reason why I advocate the max brightness setting is at the "tightened" position when this type of interface is used. So, I can tighten it and leave it there unless there is a specific need for a low mode. If the worn bezel won't maintain position in low mode, it would be less risk for me than the bezel drifting in high mode when I need it. And, it will more likely maintain position in tightened position.
One that I dreaded was the Surefire Outdoors Man. If I accidentally double tap it, then it would not say on low. I can't get an immediate high mode. Not particularly good at anything. What were they thinking?
LED vs. Incandescent
For me, it's LED. It's for a very simple reason. I don't want to rely on an equipment that its life is numbered by the days, especially when it's on daily use. I don't keep log of how long I used the bulb, and I'm not aware of a single "operator", soldier, police officer who does. Incandescent bulb will burn out. I have no way of telling when that's going to be, but since I do use the light frequently it will happen in the near future if I use incandescent. That means I have to carry a spare bulb, which is not cheap, if I use incandescent. And, there is no tangible operational benefit what so ever for me to use incandescent over LED. I'll go as far as to say for someone whose life may depend on a working light to use incandescent without carrying a spare bulb, especially when the light is regularly used, might be out of their mind. Years ago, when first Surefire line of LED came out that matched the power of 6P, I switched to Surefire LED even though it cost almost twice. L4 had only about 65 lumen back then, if I recall correctly.
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