Selfbuilt's introductory flashlight video primers

Over the years, my flashlight reviews have gotten fairly detailed, with a lot of technical data and analysis. I frequently get questions as to what all the terms mean, and how to interpret the results of my testing.

FYI, for a full list of all my reviews, please see: http://www.flashlightreviews.ca

To help provide some background, I have prepared a series of introductory overviews/primers on various aspects of flashlight form and function. These are presented in seven videos, each one corresponding to a key section of my individual reviews.

Please note that these are not intended as comprehensive examinations of the various topics, but rather as starting points to help you understand what I am referring to in my various reviews. They were recorded generally unrehearsed and unscripted, so please bear with me if I seem to ramble a little sometimes.

For more information on how I do my flashlight testing, please see my Flashlight Review Methodology page on flashlightreviews.ca: http://www.flashlightreviews.ca/method.htm

There you will find links to other specific topic pages on my site and others, explaining some of the specific aspects in more detail. You can also check out the "Round-Up Reviews" section at the top of my main flashlight review homepage for a few specific comparions of battery types, tints, etc. :wave:

Selfbuilt Flashlight Primer #1 - Introduction to the Flashlight/Torch



In this introductory primer, I introduce the general form and function of a flashlight (or torch, as those outside of North America typically call it). This is one very basic stuff, and is intended for those who find me on YouTube and are not familiar with anything more than the absolute basics (i.e., if you are already on CPF, you can probably skip this one).

Selfbuilt Flashlight Primer #2 - Build and Battery/Body Types



This segment features an overview of the common type of flashlight builds (i.e., body size, battery types, switch placement, etc.). Most of my reviews compare models of similar class, often based on the number and type of batteries used (although sometimes on their output characteristics instead). This primer helps you make sense of the various types of classes that I refer/compare to in my individual reviews.

Selfbuilt Flashlight Primer #3 - User Interface (UI)



This segment features an overview of the common user interfaces (UIs) you will find on most modern flashlights. After the build overview, my reviews typically include a discussion of the specific user interface. A wide variety of interfaces are profiled.

Selfbuilt Flashlight Primer #4 - Circuit Features



Probably my longest video in the series, this segment features an overview of what a flashlight circuit is for, and how it typically works. Most modern multi-mode (or multi-power) flashlights need a circuit to operate. I typically describe these in some detail in my reviews, with oscilloscope traces showing actual circuit characteristics.

In this primer, I spend some time discussing pulse width modulation (PWM) versus current control. I also spend some discussing inductor whine, which is believed to be the source of that annoying hum you can sometimes hear on some lights.

Selbuilt Flashlight Primer #5 - Beam Patterns and Reflectors/Optics



No set of flashlight primers would be complete without a discussion of beam patterns (and the optics that produce them). This segment features an overview focusing methods (reflectors, optics, etc.), with a discussion of the terms used to describe the resulting beam patterns (i.e., spill, flood, hotspot, throw, etc.). This will help you understand the terms that I use in the beamshot section of my reviews.

Selfbuilt Flashlight Primer #6 - Runtime Graphs



Probably the area that I receive the greatest number of questions about - how to interpret my runtime graphs. This segment features an explanation of my output/runtime graphs, where I describe what is normally included on these graphs. This will allow you to understand what each of the lines represent, and how to use them to compare the performance various lights.

Selfbuilt Flashlight Primer #7 - ANSI FL-1 Standards Explained



This segment features an overview of the ANSI/NEMA FL-1 standard for flashlight testing. This one is probably my least visually interesting primer, as I spend the whole time in the voice-over explaining what the various ANSI FL1 icons mean, and how they are actually measured/determined. But it is important to discuss ANSI testing, so you can understand the terms used in my review summary tables and discussions.

And that's it for now. :sweat: I may choose to do additional primers later, if there seems to be particular interest on a topic. But the above should help you relate better to some of the more technical details presented in my full reviews.

Again, they are really intended as introductory primers to get you started. This forum is an incredible resource, full of a lot more detailed information on the full range of topics broached in my video primers. You should also check out my Flashlight Review Methodology page on flashlightreviews.ca (http://www.flashlightreviews.ca/method.htm) for links to additional resources. :wave:

Cool stuff! When I look back over the years here at CPF I believe you were doing reviews long before anyone else. Still one of the best too!

Thanks for all your hard work and efforts~*


Sent from my iPhone 4s using Tapatalk

This should be stickied. When I first joined CPF, I was looking for something of this sort. Even though I learned a lot through reading the forums, I still learned something from these videos. (thumbs up)

Primer #7 is excellent. Thank you

Thanks.

will watch them thru thx

Awesome videos. Thanks!

While I know most of this already they will be excellent materials to educate my friends that shower me with flashlight questions all the time.

good thread

Very good informations! Thanks for your nice video & helpful explanation. :thumbsup:

A-1 Stuff...Thanks!

Glad you are enjoying the videos.

I forgot to mention it originally, but I have just updated the main post with a link to my Flashlight Review Methodology page on flashlightreviews.ca: http://www.flashlightreviews.ca/method.htm

There you will find links to other specific topic pages on my site and others, explaining some of the specific aspects in more detail. The external background links to the old flashlightreviews.com site and the current flashlightwiki.com are particularly valuable. But you will also see some specific pages I've made up on my own testing methodology.

You can also check out the "Round-Up Reviews" section at the top of my main flashlight review homepage for a few specific comparions of battery types, tints, etc. :wave:

Thank you for the interesting and informative videos, which I also found entertaining - though the latter may not have been their intended purpose . They also sparked a couple of questions, or perhaps even concerns:

1. Do you think it is possible that a light that uses pulse width modulation on lower levels may be harmful to a person's eyes if used for extended periods of time, for instance when reading on a bus? I didn't know until I watched your video that PWM means the emitter is always driven at 100%; my concern is that the pupil may not have time to contract during the very short bursts of light, like it would if you used a light that puts out hundreds of lumens (constantly) as a reading light. To put it in another way, is it possible that when using PWM, the eye is exposed to more light than a person is aware of, that it can somehow override, or "outperform" the body's reflexes?

2. My ears are in their late 30's, and although not as perceptive as they once were, they can still detect inductor whine on my Xtar WK21 if I hold it close to them. Dogs, and many other animals have much better hearing, and my second question is: It is obvious that dogs can detect inductor whine, and at frequencies that no human can hear, but is it possible that it is very annoying for them to listen to, or even painful? Most dogs would probably find a way to convey it to their owner if that were the case, but then again, it is possible that not all of them would. Perhaps the sound polluted-world we live in makes it a moot question, at least for dogs that live in the city, but if there is cause for concern I will consider using a single-mode light rather than one with PWM for dog walks in the future.

Nice... wish I would have had this to study when I first got into lights. Had to figure things out the hard way! : )
Great job!

Swede74 said:

Thank you for the interesting and informative videos, which I also found entertaining - though the latter may not have been their intended purpose .

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I strive to capture my viewer's interest, by whatever means.

1. Do you think it is possible that a light that uses pulse width modulation on lower levels may be harmful to a person's eyes if used for extended periods of time, ... To put it in another way, is it possible that when using PWM, the eye is exposed to more light than a person is aware of, that it can somehow override, or "outperform" the body's reflexes?

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I don't think there's anything to worry about. The cycling is typically many hundreds of times per second, which is faster than your pupillary reflexes. In terms of the general function of the eye, PWM is interpreted in much the same was as a camera still or my lightmeter (i.e., simply lower output). Whether it is distracting is another matter, and comes down to the sophisticated neural processing in the retina (and possibly deeper in the brain). But I wouldn't worry about it being harmful in any sense.

Dogs, and many other animals have much better hearing, and my second question is: It is obvious that dogs can detect inductor whine, and at frequencies that no human can hear, but is it possible that it is very annoying for them to listen to, or even painful? Most dogs would probably find a way to convey it to their owner if that were the case, but then again, it is possible that not all of them would.

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Since inductors are "tuned" (loosely speaking) against human hearing, it is quite possible that some lights emit ultrasonic whine. However, given that the intensity of whine is often barely noticeable in the human hearing range (i.e., high frequency but low decibels), I doubt intensity is any worse in the higher ranges dogs can hear. I am sure dogs would let you know if it bothered them (you could always experiment with your pooch's ability to discriminate, by blocking the light and seeing if they respond at all). If it was anything even approaching a dog whistle in intensity, they would let you know. As always, detection is not necessarily noxious (as any dog owner can attest when it comes to smells - they seem fascinated by things we find quite repellant!).

This thread should be a sticky in the reviews subforum.

Very informative stuff and very well done, thxs!:thumbsup:


I am curious though selfbuilt, and please don't take this the wrong way, are you a teacher by any chance, or do you have some kind formal training in this field?

Pandorum said:

I am curious though selfbuilt, and please don't take this the wrong way, are you a teacher by any chance, or do you have some kind formal training in this field?

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More accurate to say I have research training. I do give a lot of presentations, and have done some academic lecturing as well. I try to foster an informal presentation style when possible (although I am more prepared when giving an offical talk).

Fantastic stuff, thank you. Some was review and I learned quite a bit as well. Cheers!

I vote for this to be a sticky.

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Very nice and detailed infos, really helpful for newbie!