Page 1 of 3 123 LastLast
Results 1 to 10 of 30

Thread: RFI: Defensive Use of Light

  1. #1
    Marginally Relevant NH Shooter's Avatar
    Join Date
    Sep 2014
    Location
    New Hampshire, U.S.A.

    RFI: Defensive Use of Light

    I am in the process of writing an instructional article on the use of white light for defensive purposes. Specifically, in the typical low-light conditions that many attacks occur, how much light is needed to induce flash blindness of enough intensity and duration to evade/escape the attack.

    While there is plenty of information available on using a flashlight for SA and with a firearm to PID a target, there is little documentation of how much light is needed to temporarily blind an assailant. This is my goal: to determine how much light (in luminous intensity) under a variety of ambient lighting levels is needed for the light itself to serve as a viable non-lethal self-defense tool.

    Back in November, @HALO51 reached out to me for some advice on specifying a flashlight for his warrant arrest work, which generally involves forced-entry and subduing uncooperative suspects. He related to me flashlights he had used in the past and based on that, I made some suggestions on what might work better for him. Based on his results with the new light (a Malkoff MD3-M91T) and its known lumen and lux capacity, a baseline of required output capacity is beginning to form. I'll leave it to HALO51 to elaborate on his results if he wishes to, but based on his feedback it's obvious that today's high-powered LED flashlights are bright enough to induce observable temporary flash blindness in subjects under typical indoor ambient lighting levels (the higher the ambient light level, the more difficult to induce temporary flash blindness). My sincere thanks to HALO51 for sharing his experience with me and inspiring me to investigate this topic further!

    I am hoping other P-F LEO members might be willing to share their experience as part of this case study. If anyone would like to contribute data points, here is the info I'm looking for;

    1. Flashlight used: make, model and if available, its rated lumen and candela output
    2. Incident took place indoors or outdoors
    3. Ambient light conditions (near total darkness, street lighting, normal interior lighting, etc.)
    4. Distance to subject
    5. Subject state of mind (submissive, agitated, etc.)
    6. Effect of light on subject (from no effect to incapacitated)
    7. How long did the effect last
    8. Response of subject to having light projected into eyes (from submission to violent response)

    Feel free to post your info below as a response, or PM me if you would prefer to respond confidentially.

    My thanks in advance to all who feel inclined to contribute!

  2. #2
    I am writing an article as well, specifically covering higher than normally available candela and flightlight use against combative persons. This info would be interesting to be as well.

    For the data...

    Flashlight used: make, model and if available, its rated lumen and candela output
    Modlite OKW head on a rifle
    Incident took place indoors or outdoors
    indoors
    Ambient light conditions (near total darkness, street lighting, normal interior lighting, etc.)
    near-complete darknes
    Distance to subject
    6ish yards
    Subject state of mind (submissive, agitated, etc.)
    combative, holding a knife
    Effect of light on subject (from no effect to incapacitated)
    completely blinded or "bleached"
    How long did the effect last
    several minutes, taken to hospital
    Response of subject to having light projected into eyes (from submission to violent response)
    dropped knife, covered eyes, turned away, started screaming
    Last edited by voodoo_man; 01-01-2020 at 04:34 AM.
    VDMSR.com
    Chief Developer for V Development Group
    Everything I post I do so as a private individual who is not representing any company or organization.

  3. #3
    Marginally Relevant NH Shooter's Avatar
    Join Date
    Sep 2014
    Location
    New Hampshire, U.S.A.
    vm, thanks for the data points!

    My guess is that 69k candela is going to do the job even in significantly higher ambient light levels. Your experience confirms that light alone can take the fight out of a combatant if it's applied in a large enough dose.
    Last edited by NH Shooter; 01-01-2020 at 06:22 AM.

  4. #4
    Quote Originally Posted by NH Shooter View Post
    vm, thanks for the data points!

    My guess is that 69k candela is going to do the job even in significantly higher ambient light levels. Your experience confirms that light alone can take the fight out of a combatant if it's applied in a large enough dose.
    Anecdotal at best, single situation type of experience. I have a handheld that I'm going carry on duty and off duty to see if I can apply as effectively. I previously used a streamlight led hl ds stinger and it did the trick but it's not an offensive light by any means.
    VDMSR.com
    Chief Developer for V Development Group
    Everything I post I do so as a private individual who is not representing any company or organization.

  5. #5
    Marginally Relevant NH Shooter's Avatar
    Join Date
    Sep 2014
    Location
    New Hampshire, U.S.A.
    Quote Originally Posted by voodoo_man View Post
    Anecdotal at best, single situation type of experience.
    Without a doubt. But with a better understanding of the physiological aspects of flash blindness in combination with even just anecdotal evidence, especially with the higher powered lights, should prove enlightening (no puns @blues intended).

    My guess is that the recent evolution of LED lights may be opening the door to new possibilities.

  6. #6
    Quote Originally Posted by NH Shooter View Post
    Without a doubt. But with a better understanding of the physiological aspects of flash blindness in combination with even just anecdotal evidence, especially with the higher powered lights, should prove enlightening (no puns @blues intended).

    My guess is that the recent evolution of LED lights may be opening the door to new possibilities.
    I, for one, want the most possible candela out of an 18650 battery. Sure that's probably the modlite okw in it's current form but once someone whose got the time and ability to figure out where the immediate light-to-eye pain threshold is at what number of candela I want that in my tool kit. It'll happen sooner than later I believe and using a light offensively is something that has been done for many decades but now it go beyond just visually denying sight, I want the person to experience pain in a less than lethal means, without permanent injury. I think the okw head is probably a good starting point
    VDMSR.com
    Chief Developer for V Development Group
    Everything I post I do so as a private individual who is not representing any company or organization.

  7. #7
    This wasn’t me, but I was there for it.

    Flashlight used: make, model and if available, its rated lumen and candela output

    TLR-1 mounted on a 1911

    Incident took place indoors or outdoors

    Indoors

    Ambient light conditions (near total darkness, street lighting, normal interior lighting, etc.)

    Darkness outside, mostly dark inside

    Distance to subject

    7 yards or less

    Subject state of mind (submissive, agitated, etc.)

    Ready to fight, armed with handgun

    Effect of light on subject (from no effect to incapacitated)

    The light was on strobe, disoriented the suspect and he dropped his handgun, shielded eyes

    How long did the effect last

    It was seconds before he was run over by the shield-man

    Response of subject to having light projected into eyes (from submission to violent response)

    Disorientation, submission

    I was of the opinion that he needed to be shot, but it worked out.

  8. #8
    Marginally Relevant NH Shooter's Avatar
    Join Date
    Sep 2014
    Location
    New Hampshire, U.S.A.
    TC215, thanks for the data point!

    To voodoo_man's point, it's going to take some research to determine how much more brightness, which is always a measure of luminous intensity (candela not lumens), it's going to take to get the same effect when eyesight is adjusted to higher ambient light levels. A light that produced the desired result in total or near-total darkness may not deliver the same results in normal interior lighting levels (think the light level in the typical restaurant).

    High candela is typically achieved through focusing the beam more narrowly at the expense of spill. For example, the "old" Streamlight Super Tac X is rated at 200 lumens but with 40,000 candela, a 200:1 candela-to-lumens ratio. Its beam is laser-like with little-to-no spill, which can compromise SA for the way a handheld light is typically used for defensive purposes. The OKW head with a rating of 680 lumens/69,000 candela is obviously much more capable and with more lumens in the spill at a 100:1 ratio, but that's still a very focused beam - which is ideal for a rifle WML. I agree with the statement on the Modlite website that states if in doubt, their PLH light (1,500 lumens/29,000 candela) is a better choice for general use.

    Part of what I'm attempting to do is find the sweet spot of beam profile (ratio of candela to lumens) that provides adequate spill for SA yet provides enough candela to achieve the effects described by voodoo_man and TC215. I suspect there will also be a minimum candela required to achieve theses results in the typical lower-light conditions predators try to use to their advantage.
    Last edited by NH Shooter; 01-01-2020 at 02:25 PM.

  9. #9
    Site Supporter
    Join Date
    Aug 2011
    Location
    TEXAS !
    IME across multiple real world incidents and FOF training evolutions as a participant, role player and instructor you are not going to get actual “flash blindness” or incapacitation. With enough light, applied directly to the eyes, you get temporary disorientation. Thats it. Whether that disorientation buys you time to act as they fight through it or it causes the opponent to quit depends on the individual. Their mindset, “heart” training etc all play a role. There is no magic number of lumens or candela that’s going to have x effect on everyone. More light is better but I find the use of the term flash blindness and incapacitation in this context disingenuous.

  10. #10
    keep back 200 feet blues's Avatar
    Join Date
    Aug 2016
    Location
    blue ridge mtns
    So you mean that my flashlight isn't gonna make the bad guy do the chicken? How depressing...I feel cheated.
    "Bad men need nothing more to compass their ends, than that good men should look on and do nothing." - John Stuart Mill, 1867

User Tag List

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •