Help a noob out

[TwinBlade]

I am having a hard time coming up with a search topic regarding terminology. I understand a few things regarding LED flashlights but have a few hang ups.

What is PWM and what are crenalations? (sp.?) Also, what are artifacts?

Also, I assume throw is distance correct?

Yeah, I am pretty green on this stuff. If it were guns or knives, I would be doing the educating, but now I am the student. LOL!

TIA

 

[AnAppleSnail]

I am having a hard time coming up with a search topic regarding terminology. I understand a few things regarding LED flashlights but have a few hang ups.

What is PWM and what are crenalations? (sp.?) Also, what are artifacts?

Also, I assume throw is distance correct?

Yeah, I am pretty green on this stuff. If it were guns or knives, I would be doing the educating, but now I am the student. LOL!

TIA

PWM is Pulse Width Modulation - there's plenty of guides out there.
Crenelation = strike bezel. Some people think they'll be hitting folks with their flashlights.
Artifacts = beam artifacts. Again, plenty to read.
Throw is "I feel like I can see things far away with this light." It's often 'measured' by lux numbers (light output per area)

Research will be your friend for a while yet

 

[SmurfTacular]

If I where in your position, I would base my topic about the efficiency of LED's and how much they have improved over the years. The LED company Cree is in production of a new LED that has the efficiency of 160 lumens per watt. To put that into perspective, 80 lumens per watt for an LED would have been considered unachieveable 5 years ago. Incandescent bulbs average around 10 lumens per watt. Soon all lighting will be LED, its only a matter of time.

 

[TwinBlade]

Adding "beam" to artifact will help I am sure.

The problem with my search, is when I search for "artifact" say, I get all sorts of posts that say the word artifact...not what it actually is by definition. Same with other searches.

Thanks for your time.

 

[SmurfTacular]

Beam artifact quite simply is the dark spots found in the beam profile

Here is a puicture I found floating around here. The rings, and dark spot you see in the pictures are examples of artifact.

 

[GunnarGG]

Artefacts are stuff thats not supposed/intended to be there but is there anyway for some reason (imperfections in the construction?). If you look at all the beautyful beamshots that are around at CPF you will see that most look much better than those in SmurfTaculars post that shows alot of artefacts.
I have scratched the lens a little on my very nice SC30w and have some discrete artefacts from that.
If you have dust on the sensor in a digital camera you get small dark dots in your photos - artefacts.
Most lights discussed on CPF is of high quality and the artefacts are often so small that it doesn't affect the beam in real use even if it is seen against a white wall


About PWM, if you move a light rapidly in front of you looking at the LED you will see it like a line of lightdots if it has PWM.
If you shine a light with slow PWM at a fast moving object you might get a stroboscopic effect. Most lights with PWM has a frequense that is high enough not to bother.
I have a ITP A3 that has PWM that is a little slow and I can sometimes notice it during ordinary use but not so much that it is a problem

 

[TwinBlade]

Great stuff folks. Thanks.:thumbsup:

I have an iTP A1 and an A3 and have never noticed anything regarding PWM, which if I understand it correctly is basically glorified flicker? Then again, is it something you would notice if not looking for it?

I am up to speed on artifacts now. Most of my flashlights, just like you said, do not have anything really noticeable...even the cheaper A1 and A3.

 

[TwitchALot]

Carrot's guide to high-end flashlights is a good start if you're looking for more general information.

 

[TwinBlade]

Cool. Lots of info there. I bookmarked it for later. Thanks man.:thumbsup:

 

[TwitchALot]

Cool. Lots of info there. I bookmarked it for later. Thanks man.:thumbsup:

No problem. Enjoy!

 

[cistallus]

Twinblade, if you haven't already, also check out the Wiki (scroll to the bottom of the front page for Terminology) at http://www.cpfwiki.com/Wiki/index.php/Main_Page and also The Welcome Mat at http://www.candlepowerforums.com/vb/showthread.php?t=277224

 

[TwinBlade]

I have not checked out either. They are bookmarked as well.

I appreciate this overwhelming response of info folks. :thumbsup:

 

[TwitchALot]

I have not checked out either. They are bookmarked as well.

I appreciate this overwhelming response of info folks. :thumbsup:

:Whisper: That'll keep him off our backs for a few days! :Whisper: I mean, Welcome to CPF!

Good call on the WM and Wiki cis!

 

[TwinBlade]

LOL!

I know what it is to answer a lot of questions. I am a moderator on knife forums. You can't imagine the amount of silly tactical mall ninjas that come in there asking the same thing over and over again. Putting it in perspective, it is about how you folks on these forums view crenelations on flashlights when people ask what a good one is for "self defense".

It never ends.:tired:

 

[SmurfTacular]

A knifeforums mod? Really? I think I have about 30 posts on that forum.
I have always had my eye on a BM42, but right when I found the money to buy it, I realize that it was discontinued!!! Now I'm looking for somebody on taht website who's willing to trade a BM42 for a custom Maglite of some kind...

Its funny how the knife, laser, and flashlight community are all kinda related in some way.

 

[divine]

Carrot's guide is probably a good start, but maybe he translates too much into layman's terms and oversimplifies a bit too much.

PWM, let's say you have a series of on off cycles. An easy way to get 10% output is to have a 10hz on off signal and one of those cycles will be on and 9 will be off. That would be blaringly obvious and annoying having it blink every second.

What flashlight companies do to get 10% output is have their light operating at say 2,000 hz or 2,000 blinks per second, one on and 9 off, 200 times per second. It appears to be 10% brightness, and you are likely not able to detect it.

It's easy to say that the faster you go the better, but there are happy mediums. Too fast and you lose efficiency, too slow and it becomes blinky. The tough thing to do is have a very low mode, like 0.5% brightness. If you have the light operating at 2,000 hz, you might be on 10 times per second and it might appear blinky.

Some people can see high frequency and get really annoyed by poorly done PWM. Hopefully you are not one of those people.

 

[Darvis]

LOL!

I know what it is to answer a lot of questions. I am a moderator on knife forums. You can't imagine the amount of silly tactical mall ninjas that come in there asking the same thing over and over again. Putting it in perspective, it is about how you folks on these forums view crenelations on flashlights when people ask what a good one is for "self defense".

It never ends.:tired:

The same Twinblade from EDCF, master of Kydex? If so, welcome to CPF!!!

 

[TwinBlade]

The same Twinblade from EDCF, master of Kydex? If so, welcome to CPF!!!

One in the same my friend. Same with Blade forums, jerzee devil...blah blah blah. LOL! I recognize you as well. Good to see you and thanks for the welcome.

"edit" I go by my real name on the JD, Jeff Marshall. I changed it when I got rolling with kydex sheaths and holsters.

Smurf, you are right on how all things gel in the community...don;t forget guns too. I belong to more than a couple of those forums as well and recognize a lot of good folk there as well.

Divine, I always appreciate a different point of view. I am not one of those people that see it...at least not so far. You laid that out very clearly and well explained. Thank you.:thumbsup::thumbsup::thumbsup: