A Perfect Dedome?

How about dedoming bare emitter before soldering it to al/cu base?

Having it mounted to something makes things a lot easier, even if you have to move it to a different board after the surgery.

that’s true, it’s easier to manipulate when you have a star to hold it, with bare emitter there is much more chance that something will go wrong but last time I tried to do XP-G dedoming I noticed something like rust on one side of the emitter, the place where emitter touches the al board, strange, because aluminum oxidation is white and this was something like black rust…

I have throw beam pictures that I will upload when I find a place to put them.
I glued a –116 mm focal length concave lens to black construction paper and stuck it over the led of a Sipik 68. I think the curved surface sat right on top of the dome. I unscrewed the bezel almost till it fell off to get it to focus. The XR-E image was smaller, but maybe not any brighter.
So the first order optics concept is demonstrated, but it remains to be seen if one can actually get more throw this way. I have not found an easy way to figure light loss.

With secondary lens:

Without secondary lens:

Sipik Sk68 w & w/o diverging secondary on left. UltraFire SK68 3 Mode on right.

Well this seems ok for LED wire protection but I think we can expect great lux drop if we put that direct on phosphor layer of emitter because it creates thin layer of silicone or something like that…

Maybe this thing could work without lux drop but only on phosphor layer
Liquid Glass Shield http://youtu.be/xufAQ8SHLxc

I believe that somewhere out there must be simple solution(better than wavien collar) of improving phosphor brightness of LED emitter like some kind of super glow phosphor adhesive or spray that would double lux/lumen…

But if some guy finds out how to do it he will probably keep that secret for himself :slight_smile:

Hi guys. I de domed my first LED last night! (an XM-L) I used one of those safety type razor blades and wet everything with WD40 to reduce friction of the blade going through the dome. It worked well but, I initially planned to use some silicon shock oil from my RC truck as the lube since it’s clearer and more heat resistant but, couldn’t find it at the time. My initial cut was lop sided (LED was slightly inaccessable) so had to make numerous cuts to get it right-ish. The end result was not a flat surface but a very slight dome. The LED was a neutral white something and it didn’t go through any colour shift when ‘de-domed’. Honestly, it’s pretty cool but, the beam is so thin (LED is in a maglite with a Mag LED reflector) that it’s almost annoying lol.

Do you guys dedome for fun or for practical reasons?

For me it’s about warming a too cool tint and narrowing the beam for better throw.

I just did some work on my Solarforce M3 head, removed the star and took the XM-L U2 off of the aluminum, reflowed it to copper then de-domed it in gasoline with the cutting method. It worked well, the dome broke up and eventually everything was clean but it still took around 4 hours. I then removed the driver and replaced it with an E1320 5 mode, no blinkies. Was seeing 3.45A at the tail. Thought about it for a bit, bypassed the springs with a 20ga wire and added 2 chips for a total reading now of 4.22A. Very happy with that, with the beam (whiter and narrower with considerably more throw), and with the almost white tint (it was too blue for me before). :slight_smile:

This is why we do it! lol

For me, it's all about throw - doubling the kcd usually - that's why I de-dome. I think it's great for XM-L2's because a little more than doubles kcd, but with XP-G2's, I'm seeing a reduction in amps for some reason, so not getting quite double. In a mod'ed out HD2010 or SS T08, simply awesome of 200 kcd or so. Just did a C8 fully mod'ed with a XP-G2 and measured 142 kcd. Also I've done 3 TN31's so far and get about 349 kcd as I measured (resistor mod and XM-L2 U2 on stock copper), but most likely it's higher at 360-370 kcd when measured further out at 15 meters or so.

If you are thinking of a dedicated thrower, than de-doming is a must. Still want to do my Crelant 7G9, because it does about 120 kcd now, and with adding little more amps and de-doming, should get 260-300 kcd I'm thinking.

What is KCD?
Right after reflow, when she’s still HOT, you can take a dental pick and pull up the XM-L2 dome very easy. Then less soak time in the fuel.
I reflow the emitter, tin the pads, secure the sinkpad in the pill, and flip of the dome in one heating.

120kcd would be 120,000 candela, or the light of 120,000 candles.

Nice tip on the de-dome, didn’t think about doing it then…

Anyone dedome a Convoy M2 u2 1b?

candela is the standard unit of measure for throw - ANSI/NEMA FL-1 standards, see here: http://en.wikipedia.org/wiki/Candela and here: http://flashlightwiki.com/ANSI-NEMA_FL-1. I believe this is as of 2009 on forward. The spec costs $67...

Are you sure it applies to “throw”? Or intensity of illumination, regardless of angle?

“The candela (/kænˈdɛlə/ or /kænˈdiːlə/; symbol: cd) is the SI base unit of luminous intensity; that is, power emitted by a light source in a particular direction, weighted by the luminosity function (a standardized model of the sensitivity of the human eye to different wavelengths, also known as the luminous efficiency function[4][5]). A common candle emits light with a luminous intensity of roughly one candela. If emission in some directions is blocked by an opaque barrier, the emission would still be approximately one candela in the directions that are not obscured.

The word candela means candle in Latin, as well as in many modern languages.”

Wikipedia makes reference to blocking the light in some directions and letting it go in others, but does not implicitly refer to the direction as part of the meaning of the word, only that if the light is directed it is still the same power as if it’s left to radiate randomly.

Am I misunderstanding this? It does say that the light of one candle is referred to as one candela. I really never thought of a candle as having throw. Must be missing something. Again.

Honestly not trying to argue, would simply like to understand. It all gets confusing from candela to lumens. Difficult to understand where the “standard” is, if there is one. This means a lot to me as a photographer, trying to understand the concepts as they apply to taking a beamshot. I can make a Solitaire look like a TN-31 with my camera, but that doesn’t mean it’s so. My point is that I really need to understand the base concept so my beamshots will be reliable. Guess I need to send someone with a light meter out to a designated distance to take a reading on the amount of light hitting the meter at that distance, or more specifically have that person take the meter out until it registers 1 Lux, then get a reading on the distance. And here we go again, candela, lux, lumen, I’m lost.

Lumens = total light output
candela/lux = amount of light hitting something at a certain distance, also known as intensity.

I think I know where you’re misunderstanding. Are you saying that just because it reads a certain candela reading at 1 meter, it shouldn’t be the same at 10 meters because the beam will diverge?

Well, if that’s where you’re confused this is why for some super long throwers or even multi emitter lights we test it at longer distances to make sure that the beam is already fully converged and is starting to diverge. Eg. I can test my TN31 at 1 meter and get say 150kcd. But this is because at one meter there’s a noticeable ‘black spot’ in the center oft he hotspot because the beam hasn’t fully converged yet. Therefore, I should test it at a distance which is further than the distance it is at when it converges. This is why I (and many others) will test at 10 meters, and for my TN31 at 10 meters I get 3700 candela. Then I calculate it back to 1 meter, and using the inverse sqaure law I take the distance and square it, then multiply it by the reading giving me a total of 370kcd @ 1 meter.

Now with candles, you can measure it at 1, 10 or 100 meters it doesn’t matter. It doesn’t have a reflector and the light doesn’t have a hot spot, meaning the light is always diverging. This is why lights with reflectors need to be measured at a point which is after the beam diverges.

I’ll give another example. I can measure the throw of my Skyray King (3 emitters) at 0.5 meters and again at 5 meters (nobody actually measures this close, but it backs up the explanation). At 0.5 meters, the beam is probably at it’s convergence point or close to it, so if I calculated back to 1 meter, I get (I just measured this) 59kcd. However if I measure it at a longer distance, at 5 meters which is after the convergence point and I calculate it back to 1 meter I instead get 22kcd.

Not sure if I made it any clearer, but are you still confused?

EDIT:

Tom, is your 7G9 getting 120kcd stock? If so, something may be wrong with it, because it’s only supposed to get around 55kcd stock.

Well, NEMA, ANSI, along with all major manufacturers use lumens and candela and distance. Distance is directly calculated from candela - I certainly didn't make this stuff up, and certainly don't understand it all, far less than you I'm suspecting... If the industry adopted these as the standards, I think we should be using them. It's an industry adopted standard -- they are the only current standards - I see no reason to question them or come up with alternatives. People that know a lot more than me about light, and the technology behind it, came up with these standards.

It's the only way to compare -- this is why standards are adopted, that's what's it's all about, and it certainly comes in handy for us to compare stock lights, as well as seeing how effective mods are, if part of the goal of the mod is brightness and/or intensity.

I'm not paying the $67 to get the published standard, but based on the outline they made public, light output (lumens) and peak beam intensity (candela) are the two major measurements. I'm not saying my measurements are 100% right either, I'm just trying to do the best I can with what I got, and my methods and equipment seem to match up fairly well with what the FL-1 compliant manufacturers quote for their stock lights, and I know it's not perfect, and I know people have and always will question these methods.

The spec is all about flashlights, entitled "Flashlight Basic Performance Standard". I think this explains it: http://flashlightwiki.com/Light_Output_Measurements and here: http://flashlightwiki.com/ANSI-NEMA_FL-1.

I think I see how they’re deriving it, but I don’t see how it agrees with the definition of the word. But there’s a lot that I don’t get, so I won’t open that can o worms at this particular moment. Saved em, will dwell on em some, see what sinks in. :wink:

The light of a full moon huh? At what angle? Which season? From what latitude/longitude? Would that be a full moon that’s closest to Earth, or farthest away? With snow on the ground or without? Ah, standards are so…non-standard! lol

Perhaps I’m closer to getting more accurate beamshots. Perhaps I’m further way.

10 O’clock at night, no moon, very very dark outside. Couldn’t see a few feet ahead of me walking out there.

And zoomed in, by the light of my de-domed XM-L2 T6 at 3.82A in a HD2010

The trees on the back fence line are over 500 yds away.

The catch? 3200 ISO and 25 second shutter. I can make any light look dim, or any light look bright. This is what high end camera’s do. Which is why I need to understand the parameters of the standards. Sorry, didn’t mean to be argumentative.

DBCstm I don’t thinking anyone thinks you’re being argumentative, this is a discussion forum after all.

As for photos, I use ISO 400 and shutter speed 1/100. I find that it doesn’t really matter how bright it is, as long as you keep the settings the same and it’s dim enough to be able to compare all of them. In my thread here I could have made the shutter faster to prevent the TN31 from having that saturated hot spot, but then the SRK would be too dim. These photos were taken at roughly 50 yards (50 meters for everyone else).

I can’t take photos like yours because my (old 2nd hand) dslr doesn’t handle ISO800+ very well, so I have to compensate with longer exposure times if I’m taking actual beauty shots.

As long as there’s context or a basis for comparison I think it should be fine.

Flashlights in photos can only be compared with other lights taken by and identical camera with identical settings. However when we start to use candela, lux and lumens we can compare it very easily, because the numbers are standardised (albeit have a % margin of error due to variance among meters, but one can calibrate theirs if they have more than a few lights).

Sorry to jump in, but I think that, regardless of definitions, the way that most of us (well, me and some others) “measure throw” is by:

- Using a lux meter at ‘x’ meters

  • Taking the lux reading, then calculating:

That gives “a number” that should “theoretically” be consistent among readings from different folks.

I don’t know about the definitions, etc., but at least to me, that “number” is an “relative indication” of throw, i.e., if you get 120K with your light, and I get 30K with my light, your light “throws better” than mine, and we can all pretty much agree upon that.

The same goes when I’m modding my lights and if I’m interested in “how well does it throw after my mod?”. If I make a mod, and the number goes up by 100%, then the mod made the light a “better thrower”.

I have made some changes to a couple of lights lately, the HD2010 has very noticeable difference with it’s de-dome and the way I mounted the emitter. The M3 L2P took a jump, but then the de-dome and added chips don’t really seam to have made such a huge difference. This is why I’m confused taking the pics, I’m not seeing what I expected to see.

So I guess I need a meter to get some standardization going on to help me better understand what I’m seeing and then apply that to the photo’s.

By the way, those pics were taken with a point-n-shoot. Not just any point-n-shoot, the Canon G1X. My 5DMkII does much better even.

Thanks guys, appreciate the patience.

Even though I consider myself fairly new, I think that trying to judge throw “by eye” is really hard, because there are other factors that come into play. For example, I think that color/tint can affect how we perceive a light throws. Also, I think that, in another discussion, comfy pointed out that when you have a lot of spill, that can affect how you perceive throw.

Plus, we have variations in eyes/eyesight, e.g., my eyes suck, and I have terrible night vision. I have one light that measures about 66 Klux (my Jacob A60 dedomed XM-L) and one that measures 122 Klux (my shorty STL-V6 dedomed XM-L), both consistently. I also have a shorty DST with an MT-G2 (well, the same one, but before I dedomed it) and it was measuring something like 26 Klux.

When I take those outside in the dark, I could swear that the DST/MT-G2 is way brighter than the others, but they all look like they “throw” about the same at distance.

That kind of experience was what kind of pushed me to get a lux meter :)… along with “lessons” from Tom E, et al….

Just my opinion(s)…