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Fundamentals of Low Light Part 1

Of all the techniques that I would consider the most critical, low-light training is perhaps the most neglected.  The main reason for this is usually lack of a range which will facilitate low-light live fire and the general prohibitive cost for those on a budget to attend a low-light specific course.  Because of these factors, people who can’t necessarily train or practice low-light techniques on the range or in a course are forced to do so at home, which does limit some experience gained.

Another potential issue is the ability to see what equipment works and what equipment does not work, which specific techniques (such as hand held light techniques) work and which do not, and just how many techniques to refine without adding too many of the same tool to the tool box (if such a thing is possible).  I have to say that the most complex set of fundamental skills out there revolve around low-light techniques, and because of that I wanted to discuss the impetus, methodology and offer some advice for personal practice with and without the aid of light in a low-light environment.

It’s Dark and I Can’t See S**t

Before talk about gear and techniques, let’s take a look at how nature has screwed us. We are diurnal by nature, which means we are a natural predator that prefers to hunt in the day.  When we were still hunting and gathering this was a pretty big cause for concern, so we invented fire to keep us warm and alive against those predators that did hunt in the night.  We’ve been fire dependent ever since because our eyes are built for light conditions and suffer a serious lack of performance in low-light.

The human eye, specifically the retina, has two types of light receptors; Rods and Cones.  The Rods are responsible for our low-light vision, and the Cones are best suited for color vision in light.  In low light conditions, the Cones are nearly, to totally non-functional and we must rely on the Rods to provide visual input.  Rods are sensitive to certain types of color input (green and blue) though under darkened conditions do not detect color well at all which leaves us effectively color blind in conditions considered to be low-light.

This wouldn’t be so bad if it were not for the fact that all 125 million + Rods are located on the peripheral of the retina where they don’t do much at all for direct vision.  Rods contain the pigment Rhodopsin, which requires a deep saturation in low-light conditions to allow the best visual acuity.  This saturation can take as long as 30 minutes [1] and is hindered by even brief exposures to white light.  Without the aid of a light source or night vision, visual acuity is reduced to 20/200 or less [2] which is just above the legal Mr. Magoo status of being blind.

Oh, and to make things just slightly worse, our best vision in low-light comes from perception 4 to 20 degrees outside of where we happen to be looking, which is where the Rods are the most concentrated and therefore allow for the best visual input.  As you can see, our eyes don’t do us many favors in the dark.  Though not all is lost; the Rods excel at detecting contrast movement, even in the darkness so you may perceive movement fairly easily, even if you can’t see what it was that moved.

Operating (not “operating”) in low-light

In addition to the simple physiological effects of low-light, your body and mind can and/or will experience a few other occurrences under stress.   A use of force, or working with the expectation of using force (conducting a search for a bump in the night or the guy who just smashed in your front door) is more than a little stressful.  In fact, in this situation your body is going to make a few command decisions, one of which is activating your Sympathetic Nervous System.

Your SNS does a lot of good for being in or preparing for a confrontation, though it hinders some of our abilities as well.  Just speaking on vision, SNS activation forces the pupil to dilate to allow in the maximum amount of light.  While this may sound like a good thing in low-light, the lens of the eye flattens, which severely hinders depth perception and the ability to focus on close objects (like your sights) [3] [4].  This is not something you would experience in practice or a training course unless that course is specifically focused on Stress Inoculation, so it’s important to understand that it’s going to happen.

Next we have trigger affirmation, which is (usually) a subconscious phenomenon in which stress causes a shooter to index their trigger when they have no intention of firing at that moment.  This usually occurs under the heightened stress of SNS and is more common in low-light than not, but the concern for potential for unintentional discharge of your weapon is very real.  In low-light it’s not uncommon to suddenly see a threat, or a potential threat or what you think might be a threat (and is actually a lamp or a chair).  If we are to suddenly see a threat or a “threat,” or even physically round a corner or enter a door and come face to face with another person, the risk of unintentional discharge is high in that moment.

A “startle response” or flinch is an involuntary reaction to a suddenly appearing threat, the human hand can contract with as much as 25 pounds of pressure in a startle response [5], which I don’t have to tell you is more than enough to discharge a firearm.  To further complicate things, our hands like to mimic each other, especially under stress.  If you stumble and clench to grab an object for support with your free hand, your gun hand will want to do the same thing (inter-limb interaction).  If you happen to be “affirming” the trigger at that time, a discharge is highly possible.

Cognitive Interpolation is a scientific term used to describe our mind literally filling in the visual blanks when our eyes do not get enough data to discern what something is.  This isn’t a negative; it’s a neutral or in most cases a positive attribute of our brain’s desire to keep us alive.  Peripheral vision, the act of seeing something out of the corner of our eye is the most relatable experience most people have.  You see what appears to be a person, when you shift your vision to focus on it, it is a tree, a bush, a coat rack or some other not-too-human looking object.  Why does it happen?  Your brain detects it via your vision and based on the circumstances (or in spite of them) decides it’s important and wants to know right now what it is.  Using your memory, training and life experiences, it goes right on ahead and paints a mental picture for you.  That picture is only wrong when we consciously focus on the object and realize it wasn’t what we thought it was; when our brain is right we might not even realize that the initial picture in our mind was largely guess work.

Now think of encountering a figure in low-light and perceiving what appears to be a weapon in their hands.  How much of that is actual visual detail and how much of it could be cognitive interpolation?  Again, our mind is trying to help us by referencing memory and training.  Shooters know how shooters stand and the majority of the cell phone toting public does not assume a “shooting stance” when using their phone.  If you were to use force and the object turned out to be a phone, or perhaps a blow dryer, would you have been wrong?  Not in the moment you used force.  Is there a possibility that your mind could create a mental picture that turns out to be very far from what you are actually seeing and cause you to make a mistake?  Yes.  More than any other single reason; cognitive interpolation should be the largest motivating factor for low-light training and good low-light practice.

Picking up Some Lights

At last count I lost count of how many tactical lights there are on the market. Now subtract half that number and you still have a myriad of options to choose from, at least half of which are very high quality choices.  The latest trend in flashlight technology is very high lumen output and a tendency to include a strobe feature.  You have handheld, weapon mounted and a few hybrid choices.  Brand is important as far as quality is concerned, and some manufactures have features unique to their style of light.  When it comes to budget, buy as much light as you can afford and treat the purchase as you would the purchase of something that can save your life; because that’s exactly what a light can do.

Streamlight ProTac 1L – photo by Sage Dynamics

Streamlight ProTac 1L – photo by Sage Dynamics

Everyone wants a bright light, but can a light be too bright?  Definitely; depending on the primary reason for the light (home defense, EDC, etc) a light can do more harm than good in certain environments if its brightness is overwhelming or if the light isn’t used properly.  Consider that the average home and a great deal of office buildings and retail locations have white walls.  White is universally the worst color to shine a light at, and is directly proportional to how close you are to that wall.

Backslash is the amount of light that reflects back off of an object and backsplash can be blinding.  If your light is going to be used primarily indoors, a lumen level of 150-200 is more than sufficient for the majority of non-commercial spaces.  Depending on how tight the beam focus is, a 150-200 lumen light can provide a good distance envelope in which threats can be positively identified.  If your light is going the be more for outdoor use, there is nothing wrong with pushing up to a 500 lumen or greater light, though be aware that backsplash can occur in confined urban areas as well.  Lighting techniques can help to counteract backsplash but not totally prevent it (more on that later).

Other important features on lights; a pressure sensitive tail cap (so if you drop it, it goes out), at least two brightness levels (preferably low to high instead of high to low, more on that later as well) and a reasonable size that will allow you to hold the flashlight and your firearm at the same time in a two-handed grip.  For a weapon dedicated light, I recommend one with a momentary and a constant on feature that is ergonomic to support hand manipulation.

I do not recommend having a weapon mounted light only.  A weapon light on a firearm is a weapon light, meaning whatever you put your beam on you are also pointing your weapon at (unless you use splashing techniques which will also be addressed later).  This would be a pretty clear violation of don’t point your weapon at anything you are not willing to shoot.  If you are going to be working in a hostile environment where everything is a threat until deemed otherwise, go forth and good hunting, otherwise have a handheld even if you have a weapon light (and it’s not a bad idea for door kickers and black budget ninjas to have a handheld as well).


Lastly, we have the strobe feature that has become popular in the last few years.  What does strobe do?  With sufficient brightness, blink rate and concentration it can induce vertigo, disorientation and nausea, known as Flicker Vertigo or the Bucha Effect .  Flicker Vertigo was discovered in the 1950’s by Dr. Bucha after he was asked to investigate a number of helicopter crashes.  Otherwise skilled pilots reported that they became disoriented after looking up through their spinning rotor blades, the beating blades strobed the bright sky and sunlight, causing symptoms severe enough to cause crashes [6].

Now, I’m not sure who put the strobe feature into a tactical flashlight first but I know it’s been making people in clubs lose their personal constitution since the disco era.  Does strobe provide an advantage?  It does and it doesn’t.  Strobe can disorient, but its ability to do so is reduced as your distance from the threat increases.  Strobe removes a threat’s peripheral vision; it can remove yours as well.  When focused directly on the face of a threat, I have seen no significant advantage of strobe over a solid beam of the same brightness; though do not take that as proof that there is not one.  My advice is that if you want this feature; find a light that places it at least after as solid beam setting in the switch order.

The last two features that can be of concern is run time and beam focus.  For most purposes, a light of even high lumen output should have a reliable run time for an hour or more.  The focus of the beam, either tight or wide, is entirely dependent on where you plan on using it.  I prefer a wider beam because in close quarters it’s just as useful as it is on open ground, though the same cannot be said of a tight focus beam.

How to Hold It, How to Mount It

First thing is, for a handgun mounted light, I do not like any sort of pressure switch under the trigger guard or on the grip.  Especially in the case of those that are meant to be activated with pressure from the middle finger (the under guard switches), as it’s nearly impossible (especially under stress) to draw your weapon without activating the light.  This can be of great concern to anyone who finds themselves in a situation where they need to draw their weapon without drawing attention to themselves.  We want to avoid, as much as possible, activating our light unintentionally.

The same goes for a rifle mounted light; I don’t want any pressure pad where I use a traditional grip if that grip can inadvertently activate the light when I don’t want the light on.  For a strict home defense handgun, I don’t see anything wrong with a pressure switch as there is no holster issue and the switch allows free use of your support hand if you need it while retaining the ability to activate the light, but if you want to use a pressure switch, get plenty of practice in before you commit to it.

For rifle mounted lights, I prefer either an over or under barrel mount as opposed to the 3 or 9 for the sole reason that a 3 or 9 mounting can cause barrel shadow in your peripheral vision which can be distracting.   Another advantage to a 12 or 6 mounted light is that it is cover neutral, meaning it can be utilized on left or right exposure cover/concealment without worrying about pushing out far enough to get the light in play if it’s on the inside edge of the cover you are using.

FBI technique on cover, photo by Sage Dynamics

FBI technique on cover, photo by Sage Dynamics

For handheld light techniques, just off the top of my head I can think of FBI, Harries, Graham, Chapman, Neck-Index, Keller, Hargreaves and Umbrella Syringe.  There are more of course, and a few that are exactly the same masquerading about with different names.  Everyone has a preference and that’s good, what isn’t good is only having one preference.  We don’t necessarily want to put every grip technique in the tool box, mainly because the more choices you have, the longer it takes you to make one when it really counts.

My advice is to have two solid techniques you can utilize that allow you to work the light around right and left side cover, as well as smaller “total exposure” cover like a small concrete bollard or a telephone poll. Some handheld techniques do not lend themselves well to use on your primary side, others can be complicated on your support side with odd cover objects.

One more thing to consider is that with a handheld light you are much more likely to have the light in hand before the weapon, or draw them at near the same time.  With any grip you choose, going from light-only to a two-hand grip and marrying the light to the weapon should require little to no single digit finger manipulation or posturing of your hands in general to make it work.  Keep it simple and have a plan to adapt your grip based on your environment.

Continued in parts 2.


[1] Passer and Smith (2008). Psychology: The Science of Mind and Behavior (4th ed.)
[2] American Optometric Association statistics (multiple studies)
[3] Siddle, PPCT
[4] Siddle, PPCT (1998) Cannon (1915)
[5] FLETC (1991)
[6] United States Naval Flight Surgeon’s Manual: Third Edition 1991

3 Responses to Fundamentals of Low Light Part 1

  1. Jason December 18, 2013 at 9:48 pm #

    Great article, thanks for taking the time to write it. Looking forward to part 2!

  2. VP December 18, 2013 at 9:53 pm #

    Great article. Looking forward to part 2. I especially appreciate the physiological info backed up by researched facts not mere opinion.

  3. Willy Rad December 19, 2013 at 8:49 pm #

    Awesome read and spot on. Bring on Part 2.