THE LUNASOL 20 – THE NEW BENCHMARK FOR EDC LIGHTS
Like my SF A2 thread, this thread is a hymn of praise for a single light, and also like the SF A2 thread, along the way I consider a number of other lights, as well as discuss a number of general and far-reaching topics. As such this thread isn't really a review and doesn't belong in the reviews forum, nor does it have the objectivity and disinterested point of view that usually go along with a review. I love this light. And it shows. Yet I also believe that I have good reasons for my attachment and that I am pretty well able to convey those reasons—well enough, at least, to warrant the presentation of this thread. It's long, and it's involved, and it probably isn't for everyone, but it is my hope that many will find value and interest in at least parts of it. I consider EDC lights in general, and four EDC lights in particular: the SureFire A2 and L1, and Don McLeish's (aka McGizmo) Ti-PD-S and (especially) his LunaSol 20. Thus, although I have tried to forge this thread into a coherent whole, this spread of focus means that at times it may be a bit schizophrenic, seemingly unable to decide if it is just a general discussion, or if it is all about the LunaSol 20, or if it is instead a consideration and examination of four different lights. I apologize in advance for any incoherence! So, without further ado, let's jump into a general discussion of every-day-carry:
"EDC": it's an acronym—and a concept—which has wide currency here on candlepowerforums, and yet there is surprisingly little discussion of what exactly every-day-carry means; what it entails; and why it is a useful concept, both in our discussions on the boards, and in actual usage. The essential idea is simply this: if you have something with you, on your person, day in and day out, then you will almost certainly have it with you when you need it. This EDC light (or knife or multi-tool or camera, or whatever) might not be the single best tool for the task that presents itself to you, but it's better than nothing! And it's better to have an EDC all the time than a better light only some of the time, or only in some situations.
So this immediately raises the key constraint on what is, and what isn't, an appropriate EDC light: size. You must be able to carry it on your person every day—and this means in all sorts of situations: when you are at work, when you are travelling, when you are at home, when you are dressed up, when you are in jeans and a T-shirt, etc. A SF M6 or a 2D maglite are unlikely EDC lights because of their size and weight. Granted there are some true flashaholics here (God love 'em) who do, or once did, EDC an M6 in a pouch on their belt but we shall pass these wonderful people by with an appreciative and quizzical grin on our faces. For the majority of us an EDC light is built around one or two CR123A, or smaller, batteries and will fit reasonably comfortably in one of the front pockets of a pair of denim jeans. Even for those people who intend to clip the light to their belt this rule of thumb still holds good in my experience. If you can't comfortably pocket carry it then it is not going to work on the belt, every day, in all situations either.
So that's the first and most significant design constraint on an EDC light: size. The next would probably be runtime: an EDC light that runs for only 20 minutes is simply not practical as there are so many situations that can and will arise that require more than 20 minutes of light. Spare batteries could be an option here but again, just like the SF M6 as an EDC, most of us would find that carrying both the light and a couple spare batteries is just too cumbersome. Just how much runtime is enough is up for debate, of course, and is a matter of personal preference. For me, it is an hour, minimum, and ideally I like a low level that will hit the 5 to 8 hour runtime mark, or greater. Surprisingly, in many emergencies where you need a flashlight, the long-running, dimmer light is going to be more useful than the pocket-rocket blaster that will light up the whole room brilliantly for 30 or 40 minutes.
Next on my list is multi-functionality: the more multi-purpose and useful your EDC light is, the better, as you never know what will happen. A light with more than one brightness level is a good thing, and a light with both throw and flood is even better. Much better, in fact. It is my considered opinion that an EDC light will be used to perform a variety of lighting tasks that call for both decent throw in some situations and reasonably wide and broad flood in other situations. A light that is throw-only can be adequately used for tasks that call for a flood beam, but a light that is flood-only can not throw and can not adequately substitute for a throw beam in lighting tasks that call for throw. Obviously, your mileage may (and probably will) vary, and what is and is not an ideal EDC light is a matter of personal opinion, but I believe that the majority of people would, like myself, find that EDC'ing a throw-only light presents fewer difficulties than EDC'ing a flood-only light. Given this, I will not be focusing on any of the excellent flood-only lights that others might nominate as a candidate for the benchmark EDC light. If I were to include these lights, I would pick one of the SunDrop variants, or a Mule (or L1 with Mule head). And there are many others that could be chosen for consideration, of course.
Multi-functionality leads directly into just-plain-functionality, sometimes called "ergonomics", which includes the "UI"—the "user interface", the switch, grip, and action. The UI and ergonomics are absolutely key to a light. If the switch sucks—if it just feels wrong and uncomfortable in the hand—then it really doesn't much matter how bright or white or long-running or durable it is, because you won't be carrying it! Who wants to deal with a tool that just handles poorly? Thankfully, most UI's are acceptably good, and few are so bad as to be deal breakers. Nonetheless, for me personally, the UI and ergonomics are very important. I have sold some otherwise really great lights simply because the grip or switching action weren't good or were uncomfortable. It matters. And not just on the negative side of things. Since I first held my SF A2 in my hands I knew I couldn't go back to a light with a micro-controller smart interface: one of those lights where a fast "click" switches the uC to the next level up (or down) in brightness. Many fine lights have such a UI, and I don't mean to knock it, but for me there is nothing like having instant access to two levels of light, no matter where you are in the history of on and off times or cycles. Want high? Press all the way. Want low? Press part way. That's it. That's for me. Others may find a uC light to be just as appealing as a keep-it-simple-stupid UI light, but however that may be the point is that having an EDC light that just feels and works right for you is very important.
Durability could almost go without saying, but not quite. So I'll say it: durability. An EDC light needs to be durable and rugged. It's got to last through all sorts of different carrying situations, all sorts of weather, all sorts of carry locations: in a bag, in a pocket, on a belt, on a lanyard, in air, underwater, etc.; so it can't be a delicate flower, a shelf-queen exhibition light that needs to be handled just so in order to stay functional. 'Nuff said.
Now, what all of this means is that an EDC light has many conflicting demands placed upon it, and that the design of an EDC light will necessitate many compromises and design trade-offs. The realm of EDC lights is really not for purists. (And I think that might account for why we don't talk about it as much as one would expect. We all intellectually tend to like extremes and single-minded focus: the brightest, the longest throwing, the most powerful, the highest quality, etc.)
This is why I was such a proponent of the SureFire A2 at a time when it was rather widely derided. What kind of idiot would want an A2? It wasn't the brightest. It wasn't the longest running. It wasn't the smallest. It wasn't the cheapest. It wasn't the prettiest. It wasn't the most advanced. And so on, and on and on. But all of these lacks of extremes were so for the simple reason that the A2 design represented a lot of compromises and balances and trade-offs to arrive at a whole that was greater than the sum of its parts. An EDC light par excellence. And thus, not really outstanding at any one thing. The high beam wasn't all that bright, had rings in it, had an oval hot-spot, didn't run for as long as other 2 123 lights; and the low beam had that "angry blue" in it, and wasn't smooth or very white or very bright and wasn't regulated; but, even so, the combination of all of these things added up to one really great EDC light. That's what they are: a whole lot of compromises and design trade offs that attempt to make a really useful and functional whole.
There is no "perfect" EDC light. There are only different approaches to perfection; different philosophies on how and what to trade off against something else.
The LunaSol 20 represents one such approach to EDC perfection, and, in my opinion, attains the closest mark yet. The LunaSol 20 is the new benchmark for EDC lights. That's the short of it. For the long of it, please keep reading.
PISTON-DRIVE (KISS UI)
A flashlight's UI ("user interface") is something that gets pushed into the background a bit, in favor of things like output and runtime and throw and advanced features and so on, but it is absolutely vital. The UI of a light can make or break it—for an EDC light, nothing is more important than the UI. I'll say it again: nothing is more important than the user interface, the switch, the ergonomics, the action, the contours of the body and how it fits the hand, how water-tight and corrosion-proof the light is. If a light is uncomfortable to hold or difficult to activate or cumbersome and complicated to use, it really doesn't matter how bright or white or long running it is, because you probably won't have it on your person when you need it. The best UI is a problem I have long thought about. Even from the very beginning of my flashaholic career, in fact. My first real light was an Arc AAA-LE and one of the things I found to fault with this light was the conduction of electricity through the threads joining the head and body. This joint was inherently prone to developing oxidation and contact resistance, to such a degree that a heavily used Arc AAA that had never received a cleaning at this junction, would be noticeably less bright than it was when new. I saw this first hand in a before-and-after on my brothers Arc AAA-LE when I cleaned it for him, aghast at how cruddy, dirty, oxidized, and dry the threads were.
Especially later, when I started with the TigerLight upgrades project and modding lights I gave a lot of thought to switches and circuit paths and hand grips—to the UI—and started to really see how complicated and difficult and interrelated the problem really was. This is one of the reasons the SureFire A2 LOTC impressed me so much when I first encountered it, and is something about which I waxed poetical in my SF A2 thread. Some of the issues that must be addressed by any good UI are water-tightness, ergonomics, durability, action, and electrical conductance that doesn't degrade over time due to oxidation and a build-up of contact resistance. The A2 LOTC came near to being that perfect UI, but fell short on a few counts. First, if the light was dropped switch-down, the impact would often break one or more of the three spring contacts in the switch. Second, the rubber cover over the piston wears down and weakens over time, degrading the tactile feel and action of the switch. Third, the light could only be activated from one end, and thus an underhand grip presented difficulties when you want to change levels or turn on or off. So I still pondered the problem, and you can find some discussion of it as applied to incandescent mods, in my thread The six most common issues that plague hotwire mods & a solution
Then one day I came across a review of McGizmo's first piston drive light and a shiver went down my spine and I knew "this was IT". I kid you not. It was a revelation. Here was the solution I had been looking for: something which addressed not only the functional, ergonomic aspects of a UI, but also the electrical and mechanical ones as well. The PD is a marvel of elegant and graceful design. Take a look at the mechanical drawing of this first PD light: (the PD pack has not changed in any essential way since this tme) as well as the three main components of the LunaSol 20 (head, body, and piston):
The water is kept out with two o-rings (the ideal component for such a task versus a rubber bootie), one on the piston, and one on the head, and the electrical path never goes through threads, or along Chemkoted aluminum. The mechanical design of the PD is just about as bomb-proof and rugged as it gets. Brilliant. I don't think many people realize just how many issues are solved all at once by this design! As with the SF A2, you have instant access to two levels of light, as well as constant on or momentary combinations of the two levels, tail stand (candle mode), activation from either end of the light from any of five different grips in a design that fits the hand better than any other light I have used. The action is extremely satisfying: smooth precise, definite, with the best parts of both a metal-to-metal feel, and o-ring-to-metal piston smoothness. Plus, as you can see, it is very easy to disassemble, clean, and maintain the PD UI. By contrast, I always found cleaning the inner threads of the A2 LOTC with pipe-cleaners to be tedious and difficult—recessed as they are beneath the top of the center plastic cylinder which houses the guts of the LOTC, and to which mount the three spring contacts.
I want to really stress just how ergonomic this light is and how well it fits the hand. If you've never held a McGizmo light, with one of Don's Titanium clips, you will have a hard time imagining just how close to perfect the ergonomics of this light are. So, I took a bunch of pictures that will take us down the path to understanding, without you actually handling the light yourself. OK. So, here are the four lights I will be considering (when I am doing that) in this review: the SureFire A2, the SureFire L1, the LunaSol 20, and the Ti-PD-S, pictured below from left to right:
Right at the start, it's obvious that the SF A2 is the largest and most cumbersome of the four. It is, in my experience, the largest light that can still be pocket carried without too much discomfort. The L2, which is only just a little longer is just too long for pocket carry. I know. I've tried it. But even the A2 is still just a bit too big for comfort in some situations. I never kept it in my jeans pocket when taking a long car trip, for example, but would always take the trouble to remove it first. All the other lights, however, present no such inconvenience, and any of them are more or less transparent for pocket carry: you hardly know you are carrying them until you need them or think about them.
Beyond the obvious size differences, there are far less apparent but far more important differences. Let's explore them. Here is what for me is the standard LS20 grip; what I call the overhand grip:
Notice how the first two fingers of the hand fit just so in the groove between the tail and head, and how the overall length of the light matches up nicely with the average hand (my hands are on the large side of average), with the pinkie finger resting right at the top of the head. Held this way the thumb is just about perfectly placed to activate the piston, and it is a surprisingly comfortable action. At first, after I ordered this light but before I had much of a chance to handle it, I was worried about having to jam my thumb into the flared shoulder. I was pretty sure I preferred the flat-thumb style activation switches like the SF A2, but I quickly came to really love (and prefer) the PD pack and its recessed plunger. Part of the secret, I think, is that your first finger is so close to the end of the light, and rests securely against the tail-flare. It gives your hand a nice mechanical advantage, or something like that, because despite the higher spring force of the PD over, say, the L1 or A2, I personally find the LS20 easier to depress than either of those SF lights, and with a lot more pleasing and effective action to boot.
Now, the best part of it: the clip. Check out that clip. In the grip shown above, it is kind of in a "neutral" position in the open part of the hand between the fingers and the wrist. Obviously, that is comfortable. But here's where things get really awesome! Check out what happens if you happen to just randomly grab the light in an overhand grip and your fingers land on the clip:
Look at how three fingers fit nicely on top of that clip, with the high bend in the clip naturally falling right in between the first and second fingers, and notice how the first finger is cradled between the clip screws and that high bend, and how the pinkie finger rests comfortably on the body just beyond the end-flare of the clip. It makes for a perfectly serviceable grip, creating no problems for switch activation at all. This is astonishing! Seriously, how many lights can you think of where this is the case? And it gets even better! Here's what happens if the clip ends up on the opposite side of things, so that it is sandwiched between the light and your palm:
That high bend in the clip falls exactly between the first and second finger's pads on your palm, and the very end flare-up of the clip falls precisely between the pinkie and ring finger's pads (or more usually, more forward of that, off the palm, between the two fingers themselves). The extra thickness actually kind of even improves your grip on the light. Once again. You just can't go wrong with this clip. No matter how you happen to grab the LunaSol 20 (or Ti-PD-S) the clip will only help improve the feel and grip of the light.
Contrast that with the SF A2 or L1, where there is only one way to grab the light in an overhand grip that is actually comfortable, and that is with the clip in the neutral position:
In this grip, the A2 feels pretty darn good, no question, and has the KISS UI that I love so much. But grab the light in any other rotational position and you're in for discomfort. Let's see why:
Clearly the highest part of the A2's clip is poorly positioned on the palm: right on top of the ring finger's pad, and, trust me, it is distinctly uncomfortable and unpleasant to hold it with the clip in this place. Rotate it 180 degrees and you end up with this:
It's too long for three fingers, and too short for four fingers, with the first and last fingers hanging off and uncertain, and with the other fingers having no natural position on the clip, no groove, no guide. They just don't feel good there on that slope. The L1's clip, while shorter, is definitely no better, for the very same reasons:
Even worse, if you've ever tried to clip a SF light to the inside of your pocket, you know that it's a rather unworkable carry option. The head of the light sticks up a full inch or more and jams into your thigh or waist if you sit down. It's an ergonomic disaster! See for yourself:
Contrast this with the LS20 or Ti-PD-S clipped to the inside of the pocket:
Ahhhhhh! Now that is ergonomic bliss! The highest part of the light is only just above the top of the pocket and doesn't attack you when (or if!) you sit down. Further, the light is oriented bezel down which protects the lens and puts it in a better position for an overhand grip when it is removed from the pocket.
Is this starting to feel like a Ginsu knife commercial yet? (And THAT'S NOT ALL! If you order now . . . ) LOL! Sorry. But, seriously, we're only just getting started! There are four other viable grips to the LunaSol 20 (or Ti-PD-S). Here is the underhand grip:
Once again, two fingers fit nicely into that wonderful groove between the tail-flare and the head-flare on the PD pack body, and this places the first finger and thumb just right for easy head-side twist activation. That's one of the great ergonomic triumphs of the piston drive design! You can activate the light from either end. I can't tell you how useful I find this, nor how many times I had to flip the SureFire A2 from an underhand to an overhand grip in order to be able to have UI access. No need for that on the LS20: reach into your pocket and grab it and no matter which way it is oriented, you will be able to turn it on right away. And, this combination of head-twist and tail-switch allows for the very useful ability to turn the low to constant on and still have momentary access to high, or to turn high and low both on constant, just exactly the same as the SF A2 or L1. The twisting part of the A2/L2/L1 LOTC has been transferred to the front of the light, while the momentary, piston/plunger part has remained at the rear. Honestly, I can't think of a single other EDC light that can be activated from either end. I wouldn't be surprised to learn there were others besides PD lights, but the fact that I can't think of any attests to the unusual nature of this feature of the LS20 or Ti-PD-S (or the other lights based on Don's PD pack.)
In practice, in the underhand grip, the pinkie finger tends to migrate it's tip onto the tail flare itself. It just ends up being even a bit more comfortable this way, although I suppose it would depend on your hand size:
And this is the one of the places in this section where I'm going to have to give the slight advantage to the LS20 over the Ti-PD-S. In almost every way, they are ergonomically identical, but in this case, due to its slightly shorter length, front-side activation of the Ti-PD-S is just a bit less facile:
You really have to hang the pinkie off the end in order to get a good grip on the head, which is no problem, but is a bit less comfortable than the LS20 underhand grip.
The overhand and underhand grips are the most useful, but there are three others that are also very useful in certain situations. The first of these secondary grips, and the most useful of them in my opinion, is the grip I call the index-finger activation grip. It's really useful when the light is standing nearby, bezel down, on a table or other horizontal surface, and you want to look at something on the floor, or in your lap. Just grab it with your first-finger on the piston and you can immediately light up that book or TV remote or find that cheeze-it that fell on the floor:
Keeping the high level activated in this grip for any length of time isn't all that comfortable, but you usually want the low level on these occasions anyway.
The other two grips are the cigar grip and the two-over, two-under grip:
I don't often use these two grips, but they are perfectly fine grips, made possible by the superior ergonomics and design of the PD pack and clip of the LunaSol 20 or Ti-PD-S.
Then there are the various ways to not grip the light (fancy way of talking about setting the light down): it will head-stand and tail-stand for candle mode use, and if it is set down on its side the clip will prevent it from rolling onto the floor. The bezel also has understated little scallops so that if it is turned on while head-standing, you will know it.
Finally, in this section on UI's, I just have to mention one of my favorite (and unexpected) things about the LunaSol 20:
No more rubber!
I simply never realized how much I disliked rubber booties until I had the joy of experiencing the metal piston nub of the piston-drive. I never get tired of it. It always feels good, never wears down, never moves unnaturally under pressure. It's awesome. With the A2, by contrast, I would always feel the need to replace the LOTC once a year in order to get away from that awful squishy smooth slick rubber feeling of a worn down rubber bootie.
So, as you can gather, for all these reasons and more (see "Titanium" below for more), the Ti-PD-S and LunaSol 20 have by far the best UI's and ergonomics of any light I have ever handled—even better than the SF A2 and L1, which definitely have superior ergonomics and UI's—and thus have a decided advantage, over any other light, for EDC use.
TWO LEVELS – TWO BEAMS
Multi-level lights have become quite common at this point, and many of them have flashy advanced modes that pulse the light in an SOS signal, or something equally as specialized, but very, very few of the lights currently made offer two different types of beams in addition to two (or more) levels. In my experience, there are currently only two such lights suitable for EDC use: the SureFire A2, and McGizmo's LunaSol 20. Think about that: out of all the many lights now being produced, we still have only two EDC choices if we want more than one type of beam from a single light. It's strange to me, because the combination of a low-flood and a high-throw is so incredibly useful that once you experience it for a while, you are unlikely ever to go back. A low level flood is nearly ideal for many, if not most, daily lighting requirements where what you want to look at is often at arms length or closer. At this distance a light with throw, with a good hotspot, is going to illuminate a handsbreadth's area and leave the rest in relative shadow. Reading a map with a spotlight just kind of sucks, really. A low flood, on the other hand, can be putting out a lot more total lumens without creating any areas of high intensity to cause your pupils to contract. And a low flood will light up the whole are in front of you for six or ten feet, and doesn't require you to move the flashlight all around in order to explore the space in front of you. It's just a really great, really useful beam. And having it at a low intensity makes it that much better, as it can be used at very close distances, and when your eyes are dark adapted, such as when you get up in the middle of the night.
Throw, on the other hand, is just as useful for many (if fewer) situations. And when you need throw, flood will just not do at all! A hotspot can indeed be moved around, and can be dimmed down in a multi-level light (or by closing your hand around the head in a single-level light). It may suck, but it will suffice. A flood, however, can just simply not be made to reach out for any distance. So if I have to chose only one type of beam, I always chose throw, but that is far less preferable than having BOTH types in a single light. And the geometry of a tight beam just naturally suggests power and high intensity. So, a low-flood, high-throw combination is the most versatile and effective combination you can get from a two-level, two-beam light, and is the reason why I consider the SureFire A2 and the LunaSol 20 to have, on this score, a massive advantage for EDC use.
So, right here, the LunaSol 20 appears (as was expected) as my choice, my winner, for an EDC light because it combines the superior UI and ergonomics of the PD pack with the incredible usefulness of low-flood, high-throw in a single light. If I was forced to chose between the Ti-PD-S and the SF A2, I'm not sure what I would do at this point. I would hate to go back to the A2 LOTC and a hard anodized aluminum light, after the joys of the piston-drive and the wonderful feel of titanium, but I would also hate like hell to lose a low-flood beam and have to make due with a single beam (throw) light, even if it does have two levels. Fortunately, I don't have to make that choice, as the LunaSol 20 combines the advantages of both the Ti-PD-S and the SureFire A2, and then goes one or two better. It's an amazing light!
Now, this doesn't mean it's for everyone, however. If you place an extreme importance on beam aesthetics, then the Ti-PD-S would probably be your choice, and if your budget simply wouldn't allow for a titanium McGizmo light, then the SF A2 or L1 (or some other light!) might be your choice. This thread is about my choice—the LunaSol 20—and three other lights that are all very good for EDC, in my opinion. But, I have no illusions that there is any objective truth or value to my choices! To address this situation I have tried throughout this thread to present the context and logos behind my choices, so that even if people disagree, they can still perhaps learn something nonetheless. This brings me to something I consider very important: LED light tint.
LIGHT TINT IS NOT CRI
When we're actually using a flashlight we are using the light being emitted to see objects. But when we shine a flashlight against a white wall we are using an object (the wall) to see light (the beam). This is rather the opposite of standard flashlight usage, yet despite this fact there is a widespread assumption that the tint of the light seen on the white wall will tell you how "good" it is—how well it renders colors, how it compares to other emitters or light sources, and how well it will perform in actual use. In general, this is simply not true. For example, the light from even a high quality incandescent has a yellow tint to it ("piss yellow" some would say), however despite this departure from being "white" a 3300 K CCT incandescent filament provides extremely high quality light, often deemed best for use in art galleries and for photographic studios. Conversely, the light from most fluorescent tubes is stark white, yet is deemed a poor quality light not suitable for taking photographs or even for making up your face in front of a mirror.
Strange then that for so long I believed that what I wanted from an LED flashlight was an emitter with a "white" to "warm white" tint. What I really wanted was good color rendering, but I just assumed that this was the same as good tint against a white wall. I was wrong, and the LunaSol 20 was the first light that made me fully realize this. Compared to my SureFire L2 my LunaSol 20 has a cool, slightly blue, tint to its beam, and at first I was concerned that the light wouldn't be high enough quality for my needs. Yet, as I used the LunaSol 20 I realized that despite its "tint", it was actually superior to my L2 for actual lighting tasks. I could easily distinguish color differences, and in use I never noticed a tint or skew to the light.
The issue of tint is magnified greatly when comparing lights side-by-side against a white wall. In this scenario the tint dominates all other considerations and even two "snow white" LED emitters, when put side by side like this will show up tint differences, often making you feel as if one emitter was obviously better than the other when in point of fact both might be pretty much identical.
Thus, it is my considered opinion that the best way to evaluate the quality of light from a flashlight is to actually just use it to perform a wide variety of tasks. The better the quality of light, the easier it will make them. However, this is not to say that the tint isn't important at all! While our eyes and brain will adapt to the white balance of the light we're using, it doesn't completely adapt. We notice whether we are using candles or fluorescent tubes! And most of us do have a tint (or "white balance") preference. And this is fine. Just keep in mind that the CCT (or tint or white balance) of your light doesn't necessarily tell you anything about its quality or color rendering ability.
I'm really excited about the beamshots I've put together for this review. I think they're something special and unusual. Possibly, there may be some who will agree that, yes, they are something special and unusual—something unusually, especially bad!—but I believe they are something special in a good way. The reason why some might take issue with them is that I have parted ways, more or less completely, with the conventional wisdom, the conventional method, that one must lock the aperture, shutter speed, and exposure/ISO (and even the white balance, possibly). I did not do this. I went down this path-less-taken because I felt compelled to do so. I have long been profoundly dissatisfied with beamshot pictures taken with a locked camera. I have always felt that they just didn't look much like what I experienced when using the light in person. They weren't what I actually saw. It's that simple. It makes me think of a tape recording of a class-room lecture. Have you ever heard one of those? Where your friend just set his or her tape recorder on the desk and let it record? When you listen to the recording, some sounds are greatly magnified and exaggerated, while others are muted and recessed, and still others have been lost completely. If you compare the recording with your auditory memory of the event, you come away dissatisfied. The recording is just not faithful to your experience, to what you actually heard. This is how I feel about most of the beamshots I have seen, or personally gathered, that were taken with a locked camera.
The crux of the issue is simply this: the camera is not the eye. The dynamic range of even the best digital cameras (not to mention film!) is nothing compared to the human eye. When you shine a light against a wall, your eyes are able to deal with the huge disparity in intensities presented to them, and your brain is able to compose a scene that has both the shadow details, and the hotspot details—which is a far cry from a single white circle floating in darkness that results when a camera tries to capture a scene with such a huge disparity of light intensities. Further, even setting that issue aside, the differences between lights are not seen the same by the eye as by the camera. Both in terms of total output, hotspot intensity, and color temperature (white balance), the eye and brain make immediate and unconscious adjustments that in no way correspond to a locked camera.
There are a number of factors in the conventional approach that contribute to the problem(s). First of all, using a white wall as the background is going to create the absolute largest range of light intensities. It's great for showing up differences in beam tint, and for capturing hotspot size and shape and general beam aesthetics, but if you don't over-expose the most intense of the hotspots of the lights being reviewed, then the shadows will be badly underexposed, and the dimmer lights in the line-up will look much dimmer than they really are in person. Conversely, if you try to capture more detail in the shadows and/or dimmer lights, the brightest hotspots will be seriously over-exposed, and you will lose all the information in that area. So, with this in mind, I did not use a white wall for my beamshots. I used a scene with a lot of color and texture, and with an overall reflectance somewhere in the middle of the grayscale.
Next, the conventional approach has the camera and the flashlights at basically the same distance and angle away from the beamshot surface. This makes a lot of sense, honestly, and seems the straightforward thing to do, but it also does nothing to reduce the range of light intensities that the camera will be required to capture. If you move the camera closer to the scene, the light falling across it will be somewhat more even. How much do we really care about all that dark area far away from the hotspot, anyway? Why include so much of it in the beamshot? For my setup in this review, the camera was about 5 feet from the wall, and the lights were about 8 feet; the camera was also a bit below the beamline axis, and angled up at the hotspot, in order to avoid casting shadows on the subject.
Finally, as I have already stressed, locking the camera parameters across all beamshots means that the dynamic range needed isn't just of that between the hotspot and shadows of one light, but is of that for all of them, i.e. it is the range between the hottest hotspot of all the lights, and the dimmest shadow area of all the lights. As if the situation wasn't challenging enough without making it more difficult!
So, what to do? My answer was simple: cheat. Damn straight. And I will not apologize for it, although I will explain. First, you just can't lock the camera if you're concerned with capturing the subjective human reality experienced when using a flashlight. I know all the arguments for doing so, and they are very compelling, and if you place objectivity above everything else, you will of course lock all parameters; but you just simply can't do that if what you want is to try to create pictures which come even somewhat close to being faithful to what you actually see. The main problem, as I mentioned, is lack of dynamic range. The dimmer areas, the shadows, of the dimmest lights don't end up as just lower in intensity—they end up as all ZEROS. Really, they would be negative, but in the digital language of the camera, zero is as low as it goes, so anything less is represented also as a zero. Information is lost. The same goes for the maximum intensity: turn all the bits on, and that's it, that's as high as it goes. Anything higher is just represented by the same number of bits, all turned on to 1. Thus, if you want to capture a scene with greater dynamic range than zero to highest count, you will need to take two exposures. And this is precisely what I did. In one exposure, I lost no details in the shadows, and in the other, I lost no details in the hotspot. I then combined these together in photoshop, with the shadow-exposed shot as the background, and the hotspot-exposed shot as the top layer, with a 50 percent opacity, which allowed details from both shots—information from both shots—to combine into one picture. The problem, as many readers are certainly already yelling out at the computer screen, is that I have now lost the information about which light is brighter than another. Yet, this isn't really true. The camera is only a tool used by the reviewer. I, as the reviewer, don't need the camera to tell me which light is brighter or dimmer than another! I can go out again and again to my composition area, and repeatedly experience the actual lights, the actual scenes themselves, and compare the experience with the pictures. (Plus, in my case, I pushed the exposures either up or down, to the points just before details were lost to under or over exposure, and thus the resulting composite shots were far from arbitrarily bright or dark, nor all the same brightness; they were actually already ranked up pretty closely, from dimmest to brightest, with a couple exceptions.) The thing is that once you have a composite with no lost information, you are free to use a number of adjustments on it. I used the exposure slider to darken the low-level shots, for example. And I used the lighten shadows slider to bring out that shadow detail captured by the second shot. All the time during this process, I was carefully checking the results against the realities, in order to create as faithful a facsimile to the reality as possible. That was my goal at every step of the way—to CHEAT in order TO TELL THE TRUTH. Paradoxical, to be sure, but I stand by my results. I maintain that the following beamshots are a lot closer to the realities that I experienced than any I could have gathered by locking the settings.
For those who are still not (and never will be) convinced, I have also included four shots all taken with the same settings in order to highlight the throws and hotspot characteristics of the high-levels of the lights. Although, I should mention that these four locked shots were taken of a different scene, from a different (and much greater) distance.
OK. Enough of that. Here are the beamshots. First, the SureFire A2 on low:
And the SureFire A2 on high:
Yeah, it's a great light—I love the SureFire A2—but the low beam aesthetics are poor: the flood isn't all that even, and it has the so-often-cited "angry blue" artifacts at the center. In addition, if your preference inclines you towards higher CCT white-balance, the yellow tint of the A2 high beam is going to bother you no matter what its other virtues are.
Next we have the SureFire L1 on low:
And the SureFire L1 on high:
Notice how very tight the beam is from this light. It throws like crazy (as can be seen even more clearly below in the "throw" shots I took) and has very little spill light. It's a freaking SPOTLIGHT, really. Your own personal spotlight. Which, is certainly very cool and which does have its advantages. However, the extreme lack of spill is a detriment in many situations, and the beam aesthetics from the TIR will not totally please those people who put an emphasis on such things. There might be some ringy-ness, especially in the spill area, for example. This next light has no such issues, and has one of the most perfect beams in all of flashlight-dom:
Ti-PD-S on low:
Ti-PD-S on high:
She's a beauty, to be sure! That high beam from the Ti-PD-S is one of the most beautiful I have ever had the pleasure of experiencing. However, the low beam (while still aesthetically wonderful) isn't nearly as nice or useful as the low flood beam from the LunaSol 20. See for yourself.
LunaSol 20 on low:
LunaSol 20 on high:
Part of the reason for the superiority of the LunaSol 20 low beam over the SureFire A2 low beam is the use of 3mm Nichias instead of 5mm Nichias, and the other part is that the Nichias in the LunaSol 20 aren't recessed down inside a reflector but instead sit on a flat ring around the outside top edge of the main reflector:
This design choice is why the LunaSol 20 has such a lovely low beam, but it is also why the LunaSol 20 uses an unusual LED as for it's high-throw beam, as the die size and radiation pattern of the LED must mate with a narrower, tighter, and smaller diameter reflector. Fortunately, the Osram Golden Dragon LED is just such an emitter, and despite the fact that maybe you haven't heard of it, is a very nice light source. Notice that although the Ti-PD-S high beam is brighter and more intense, that the LunaSol 20 high beam is pretty nearly as good. It isn't as bright, and it doesn't throw as far, and aesthetically is a bit less smooth, but on the whole it is, in my opinion, about 90 percent as good as the Ti-PD-S high beam, which is saying a great deal! The trade-off involved in having the LunaSol 20 high beam instead of the Ti-PD-S high beam is small, but the gain of the LunaSol 20 low beam over the Ti-PD-S low beam is HUGE.
More importantly, in regards to the LunaSol 20 beamshots, please note that the tint of the low beam is nicely matched to the tint of the high beam. As I mentioned earlier, tint tends to stand out quite a bit when LED's are put side by side, and thus the tint matching from low to high (where the three nichia low beam emitters are also on, by the way) is more important than you might think it would be. This is yet another superiority of the LunaSol 20 to the SureFire A2, whose low to high beam tint disparity is tremendous.
Moving on, next, we have four shots all taken with the same camera settings. I decided to add these shots to illustrate the throwing power and hotspots of the lights. Both the camera and the lights are pointing down at the lawn from my second story window. All lights are on high. First up is the SureFire A2:
SureFire L1: (and notice how freaking tight the beam is from the TIR optics!)
And finally, the LunaSol 20:
I also have four more shots, although I'm not sure how useful they will be to people. They are the four high-beam close-up shots of the x-rite ColorChecker chart which appears in the center of the first eight shots above. The White Balance has been adjusted for each shot in order to try to be as faithful to the colors I saw in person as possible. A locked white balance would have skewed things terribly. Sorry. Once again, SureFire A2 is first:
And the LunaSol 20 bringing up the rear:
I don't really know what people will do with these pictures, but they are kind of interesting even so.
I have to confess that when I first saw the various custom made titanium lights on CPF I had exactly the same reaction that most people have. I was like "Titanium? Doesn't it have a higher resistance than aluminum? And doesn't aluminum conduct heat better than Titanium? Why would you pay so much more for a Titanium light? I don't get it!"
Now, some people like to "answer" these questions by saying that titanium is just "bling", just "man jewelry"; that it's a status symbol kind of thing, like a Rolex watch; that if you were just thinking practically and rationally, you'd use aluminum. However, this sort of psychological write-off really isn't true, as I've come to find out both from my experience owning titanium lights, and my scientific research into the question of titanium. So, let's look a bit more deeply and more thoughtfully into the question of titanium flashlights.
Right off the bat, let's knock the electrical resistance thing on the head! Yes, titanium does indeed have 26 times higher resistivity than aluminum, but that's still pretty good. Nickel has almost 3 times greater resistivity than aluminum, and yet it is used for 1/4 inch wide .005 inch thick ribbon strap connections between cells in a welded battery pack. And those straps are often asked to conduct four or five amps or even more. Metals—all metals—are good conductors of electricity. It's sort of in the job description. Further, the amount of material involved in a flashlight body's conduction pathway is enormous. There's a lot of titanium there—many orders of magnitude greater an amount than that involved in a battery packs' nickel ribbons; more even that that in a 12 gauge wire—and thus the total circuit path resistance involved in both the aluminum and the titanium flashlight is so low as to be insignificant.
Most of the time, that is . . . because the story of electrical resistance doesn't end there. The thing is that both aluminum and titanium (and most metals) oxidize in air, and a surface layer forms, which may or may not be conductive. Aluminum's surface oxide layer is most emphatically NOT very conductive. This is why aluminum lights are Chemkoted so that they have a different surface layer that is electrically conductive, and which is environmentally stable and corrosion resistant. Otherwise, any bare aluminum to aluminum joints in the conduction pathway will eventually develop significant resistance, totally negating the low resistivity of pure aluminum. Titanium's surface oxide layer, in sharp contrast, conducts electricity just fine and bare titanium to bare titanium is a totally viable and environmentally stable corrosion resistant joint just as it is with no special treatment. So, if we were to reckon up titanium's advantages, ironically "electrical conductivity" might actually be one of them, considering it's surface oxide, but you could argue against this view if you have complete trust in the Chemkote surface layer on the aluminum light.
Heat Conductivity – The Long Version
Heat conductivity is a much more complicated consideration, unfortunately. I will show below that regardless of any theoretical calculations and discussions that may follow, the LunaSol 20 manages heat very well even in worst case scenarios (as does the Ti-PD-S), and honestly, I don't know why that should surprise anyone as many plastic LED lights exist that also perform just fine, if it comes to that, and I can guarantee you that titanium has better heat conductivity than any plastic. However, let's take a look at the heat transfer problem from the theoretical perspective, just for fun. And don't blame me if it starts to get a little tedious! Feel free to skip the rest of this section at any point and jump to "Heat Conductivity – The Short Version" below.
Heat transfer can happen via conduction, convection, or radiation, and a general heat transfer scenario is painfully difficult to calculate theoretically. Conductive heat transfer, or transfer scenarios dominated by conduction, or which can be reduced to an equivalent conductive (and thus simpler) problem, are much easier to deal with, and can be thought of just like an electrical resistance problem with wires and current and voltage and a number of resistors. The current is the heat flow and the resistors are the junctions or conductive elements. An LED, like a transistor or MOSFET, has a degrees C/W rating, which predicts what the temperature drop across the junction will be when a certain number of watts are dissipated through the device. This is analogous to a resistor's voltage drop when a known current flows through it. The equation is very simple:
dQ/dT = deltaT / R
q = deltaT / R
where dQ/dt is the rate of heat flow in watts, deltaT is the temperature difference, and R is the resistance of the junction (or in general, of the material conducting the heat flow). For simplicity, I will let small q = dQ/dt. Some may recognize this as Newton's Law of Cooling, by the way. So, for example, a 10 C/W junction dissipating 2 watts, will have a 20 degrees C temperature differential across it. This, however, doesn't tell you the die temperature unless you know the temperature of the other side of the junction—usually a heat sink. The heat sink, in turn, has a temperature drop across it. This can be calculated by expanding the "R" term above. For a simple rectangular block of material:
R = L / (k * A)
where L is the length over which the heat must flow, k is the thermal conductivity, and A is the area through which the heat must flow. Notice that R increases with L, but decreases with both k and A. Notice also the k must have units of watts / ( meters * degrees C), although usually it appears as degrees Kelvin, actually, but 1 degree C = 1 degree K for differences, as Kelvin is just Celsius with a different zero. This makes R have units of (degrees C / watts), which you can work out for yourself if you wish.
Sadly, the MCPCB heat sink in the LunaSol 20 isn't rectangular, with the area constant across the length of heat flow. The Golden Dragon LED is at the center of a disc of aluminum, and thus heat flows out from the center to the edges, and also out of the top and bottom. Since I want to calculate a worst case scenario, and because the top and bottom are much more complicated heat transfer situations, I will pretend that no heat escapes from the top or bottom of the .75 inch diameter, 2 mm thick heat sink. Now, if we think of a very thin cylinder where heat flows from the inside to the outside, it should be clear that the rectangular equation above easily applies because the cylinder can be unfolded, without any significant distortion, to a rectangle of 2*pi*radius width, h height, and t thickness, where t is small. If t were large, then we couldn't unfold it without distortion. But, with that in mind, we can think of the MCPCB heat sink as a big collection of nesting cylinders, all which have a small thickness, and then we can just add them up. Such is the power of integral calculus! LOL! So, thickness becomes dr, width is 2*pi*r, and height is still h. Rearranging terms above we get:
deltaT = q / k * integral (dr / (2*pi*r*h)) from r=inside to r=outside
We can pull 2, pi, and h from inside the integral as they are constants:
deltaT = q / (2*pi*k*h) * integral (dr/r) from r=inside to r=outside
But the integral of dr/r is just ln(r), so,
deltaT = q / (2*3.14159*237W*m^-1*K^-1 * .002m) * (ln(.375inch) – ln(.125inch))
deltaT = q / (2*3.14159*237W*m^-1*K^-1 * .002m) * (ln(.375/.125))
To determine q, we can put an upper limit on the heat dissipated by just making it equal to the power of the light. (The actual heat dissipated would be less than this, as some of the power goes into the production of light energy.) Back of the envelope calculation of that is simple: take the Wh of a CR123A cell and divide by the runtime in hours. The Wh of a good CR123A cell at a .5 amp draw rate (the current to the Golden Dragon is 425 mA) is right around 3.7Wh. This makes for 1.85 Watts due to the 2 hour runtime of the LunaSol 20 on high. So q = 1.85W, and to clean up some more, .375/.125 = 3, and ln3 = 1.0986. Here's what we have now:
deltaT = 1.85 / (6.28318*.002*237)*1.0986 K
where I canceled some units and moved K^-1 at the bottom to K at the top. Work this out and we get the result:
deltaT(heatsink) = 0.68 degrees C
This is the drop across the heat sink. And we can also add to that the drop across the LED to MCPCB solder joint. From the spec sheet the Golden Dragon has an 11 C/W thermal resistance. So, q*R will give us a result of
deltaT(junction) = 20.35 degrees C
Having fun yet? Let's move on to the temperature drop across the titanium body. Using the entire body for the calculations would be too optimistic, because the heat has to flow from the heat sink to head mating surface, and then all the way down the body before it gets to the tail, and this doesn't happen without a temperature drop. The tail section does indeed draw away a significant amount of heat, but since that is hard to calculate, and since I'm interested in a worst case scenario, I will pretend that the titanium body only consists of the head (with maybe a bit extra length to partially compensate). So, I will use a .125 inch thick, 1.5 inch high, 1 inch outer diameter cylinder. It is interesting to compare the simple rectangular equation's results with our more accurate one in this case, since the thickness (.125 inches) is not exactly large with respect to the diameter (1 inch), but I will leave that as homework. (Yes, I'm having fun with this. *cough* Sorry. *sheepish grin*) OK. So, let's use the same formula, but this time we use titanium's heat conductivity of 21.9W*m^-1*K^-1, an h of .0381m, an inner radius of .375inches, an outer radius of .5inches. The result is,
deltaT(titanium case) = .10 degrees C.
MY GOD! That's crazy! Clearly we needed aluminum there, didn't we? After all, if we had used aluminum, the result would have been,
deltaT(aluminum case) = .009 degrees C,
and isn't that a whole order of magnitude better, after all?
Now, I've left two important pieces out so far, and those are the case to air junction and the heat sink to case, and MCPCB solder joint to heat sink contact resistances. If you take any two blocks of materials, A and B, and push them together, and cause heat to flow, there will be a discontinuity of the temperature from the left end of A, to the right end of B, where they meet. This is called the thermal contact resistance, and it is notoriously difficult to calculate. I don't know much about it, but I did do enough research to know two things: a value of .5 C*in^2*W^-1 for our situation is conservative, and that contact pressure is the most important parameter for smooth mating surfaces with little to no air gap (hence the need for heat sink grease in such cases, by the way). Why do I mention the pressure thing? Well, when aluminum heats up, it expands at a greater rate than titanium which greatly increases the contact pressure on that mating surface, ensuring a nice thermal joint there. It's a nice side benefit to using a titanium body in your flashlight. Anyway, moving on, the delta T across that junction will just be q * (Rc / A) where A is the area, which we calculate from a .75inch diameter and a 2mm height. Thus,
deltaT(heatsink to case junction) = 1.85 W * .5 C * inch^2* W^-1 / (pi*d*h)
deltaT(heatsink to case junction) = 1.85 * (.5 / (3.14159*.750*.07874) C
deltaT(heatsink to case junction) = 4.99 degrees C
For the solder joint to heat sink junction, we need to use an area of .45 in by .4 in (from the golden dragon spec sheet), which yields
deltaT(solder pad to heatsink junction) = 5.14 degrees C
Now, all that's left is the case to air junction. Oh, that's all, is it? Good grief! Calculating that from theoretical considerations would not be trivial. What I can tell you about it is that the greater conductivity of aluminum wouldn't play much of a role. Here, emissivity is more important, and titanium has a pretty good emissivity, although hard anodized aluminum is also good. I'm not going to get into any numbers or make any arguments. This part of the thread is already way too long. All I am going to do is to steal some of Don's measurements. And thank God for those. Nothing like predicting reality from reality. OK. So, Don set up an FLIR measurement and measured 47.7 C at the hottest part of the head, and this was a worst case scenario, being constant on just sitting in open air. See for yourself, as the setup is kind of neat, and I already uploaded those pics to my server space:
Note that the ambient temperature was over 28 C! Which means that the temperature delta from head to air was 19.2 C, yielding an R value of 10.4—very close to the R of the Golden Dragon LED itself, interestingly enough. More importantly, though, consider that if the air had been at 20 C, then the head would have been just below 40 C instead of 47.7 C. But, again, since we are interested in the worse case scenario, let's use the 47.7 C value.
So, let's add it all up
47.7C + 0.10C + 4.99C + 5.14C + 0.68C + 20.35C
die temperature of LED = 78.96 C,
and the maximum junction temperature of the Golden Dragon LED is 125 C.
So, note a number of things here. First, that even in a worst case scenario and making an upper bound sort of estimate, the die temp is well within limits. Second, notice that the largest contributions to the die temperature do not come from the heat conductances of the aluminum or titanium parts, but rather come from the body to air junction and the LED junction. They dominate the calculation. And the next largest component comes from the contact resistances. So . . . maybe we could all please agree that titanium's thermal and electrical "disadvantages" are non-issues for most flashlight use situations?
Heat Conductivity – The Short Version
There was actually a much easier way to demonstrate that the LunaSol 20's die temperature is well below the limit, and that is to look at the runtime / output plot which appears below.
Note that the output does not diminish with runtime. If the thermal situation was pushing the edge, then the output would start at a maximum then ramp down to a lower level due to rising die temperature, which causes loss of efficiency and output over a low temperature die running the same current. This is something I have seen before in multi-level flashlights. It happened with the Arc4 and appeared in this_is_nascar's output graphs of the Arc4 at various levels. The highest level graph showed this ramp down, and TIN complained about it, and Peter Gransee told him it was thermal and that if he just held onto the light the whole time it wouldn't happen. TIN did that, and lo and behold, the output stayed at the high starting level for the whole run due to the lower surface temperature of the body of the light (and thus also of the die) when held by TIN's hand.
Still, I have yet to say anything about what the advantages of titanium are. All I have done is shown that its disadvantages aren't really all that significant in the case of the LunaSol 20 (or Ti-PD-S). What are the advantages? Why pay a premium for a titanium light?
Titanium is durable, beautiful, pleasant to handle, and is repairable.
By "durable" I do not mean that it has a greater yield strength than aluminum, or anything like that (although it does). I mean that a titanium light will weather the slings and arrows of outrageous fortune with aplomb and poise. Scratches and dents just become part of the patina and do not detract from the appearance or function of the light. Hard anodize is harder than titanium on the rockwell scale, it is true, but the problem is that the aluminum substrate underneath is fairly soft and flexible. Drop your HA light onto concrete or other hard surface, and the aluminum at the impact point will deform—if only for a moment—and the brittle anodize there will flake off, leaving bare aluminum exposed. This not only looks horrible, but if it happens over enough of the surface of the light, can result in significant surface degradation over time. My brother has a hard anodized Arc AAA where all of the hard anodize is gone from the knurl points, leaving rounded bare aluminum over most of the light. It neither looks nor feels good, although I admit that it is still serviceable. If you care at all about aesthetics, titanium is a great advantage. It means that your light will continue to look and feel great for as long as you care to own it, even if the light suffers extraordinary damage.
Here's a great example: one Ti-PD, along with its owner, was involved in a motor cycle accident, and suffered a great deal of abrasion and scarring. The important thing is that the owner wasn't seriously injured in the accident, but of interest to us here, is what happened to his Ti-PD:
Nasty, ugly damage there! But, after some love and attention with sandpaper, files, and metal polish, look at the result:
Not bad, eh? Pretty damned good, in fact. Try that with a hard anodized aluminum light! This is what I mean by durable. If you want to, you can keep a titanium light looking beautiful and feeling great for a lifetime.
And, I want to stress just how great Don's titanium lights do feel. I've never handled any metal tool that I like anywhere near as much as my LunaSol 20. It feels amazing—SO much better than any of my hard anodized SureFire lights. There's just something about titanium. It has a warmth and luster and richness to it, both visual and tactile, that simply must be experienced in person to be believed. Added onto that, of course, is the design of the PD pack, with it's wonderful, ergonomic, concentric grooves and tail flare, that allow for a good grip, while at the same time not getting in the way of the wonderful feel of the titanium. Knurling would result in a markedly inferior feel and ergonomics, in my opinion. Finally, if you live or play near salt-water, titanium is a great advantage, having superior corrosion resistance to salt water (and to almost everything else, for that matter).
So, do you need titanium? No, especially not if cost is an issue. But, do you want titanium? HELL YES, especially if you've ever experienced owning a titanium light before.
There is still yet one other perspective from which to view titanium, and that is from the perspective of the small custom light maker. If you are your only employee, you simply cannot do huge batches of lights. You have neither the capital, nor the labor, to handle a large run, and thus you must produce lights in small batches. This is a definite strike against HA aluminum lights because such lights must be both Chemkoted and anodized—processes which are expensive to do in small batches, and which are only economical in large batches. From the consumers point of view, you could say this is irrelevant, but even as a consumer, I personally care about the economical viability of small time light makers. I want them to be able to make a profit and continue to offer the lights and services which they do offer. If that means titanium, so much the better!
SOME BUYING ADVICE
Before closing, I'd like to say a few words of advice about buying high-end, expensive custom lights. Many people here, flashaholics though we all are, have never paid $400 or $500 for a flashlight, and consider the idea sheer insanity, or totally impractical, and that's fine. If $500 isn't in your budget, then it isn't in your budget. For some people, however, it is in their budget fiscally, but psychologically they have to go way out on a limb to "justify" it, and thus end up placing a great weight of high expectations on their expensive custom light. They end up losing perspective and stress out over any little defect in the finish of the light or the tint of the beam or what-not. This is no way to have a good high-end light experience! Take some advice from me on this one: if you have to go so far out on a limb to justify a LunaSol 20 or Ti-PD-S or other custom light, and will be disappointed with anything less than "perfection", then you'd best wait until you are in a better frame of mind before taking the plunge.
Ideally, you want to forget about the price altogether after you have paid it. You want to give the light a fair chance, a fair evaluation. I would suggest that you don't evaluate the light too quickly, nor only intellectually. Just use it. Rest assured that you can always sell it later if you decide against it, but for at least a couple weeks, just give it a chance and use it, and by "use" I do NOT mean to constantly compare it against your other lights and constantly shine it against a white wall to decide if it really is all that and a bag of chips. Rather, I mean use it for when you actually need a flashlight: EDC it, in other words. Let the experience and truth of the light unfold itself to you slowly and in its own way and time.
Specifically for the LunaSol 20, I would suggest that the PD action will probably exercise muscles which you've never had much call to work out before. It is going to take a little time for those muscles to develop, but it is TOTALLY WORTH IT. Invest the time and effort to do just a small amount of adapting to your new light. The PD action is awesome, one of my absolute favorite's, but it did take a week or two for me to get used to it and to build up a few appropriate hand muscles. For the first few days I found it a little strange and a little difficult to hold high constant on. That's probably normal, and if your experience is anything like mine, it will pass in short order, leaving you with a strong appreciation and preference for PD lights. Or, it's possible that you still might not like it, of course, and that's fine. It'd just be a shame to reject it in the first week because you found it difficult to activate. Also, I should mention that you can always substitute a weaker spring and/or cut the top loop or two off the existing spring, if you really decide a weaker spring-force is for you.
Over the long term, I would also suggest that you JUST USE YOUR LIGHT! Do NOT put it in a box or on a shelf because you are too afraid to use such an expensive light. A LunaSol 20 or Ti-PD-S or SunDrop shelf-queen is a terrible waste! Don't let these wonderful lights suffer such a fate! I mean, if that's what you want then fine. No problem. But just don't let fear and trepidation and constant awareness of the cost of these lights keep you from using them. Do yourself a favor, and put them through their paces. Use 'em hard. That's when the LunaSol 20 will really shine.
OK, well dear reader, thank you so much for bearing with me, even part way. I know this is an outrageously long thread! I hope you have found something of value in it, and I hope that more people will experience the joy of owning and using one of McGizmo's amazing custom lights. It's highly likely that you won't regret it! For myself, the LunaSol 20 was a flashaholic-career changing light. A turning point, after which I could never see lights exactly the same way again. And after such an amazing encounter—a continuing encounter—I can only offer up this thread as the most appropriate thanks to its maker! Thank you Don for an amazing, amazing light. I appreciate it every, single, day! May this thread do even a small fraction of justice to this amazing light.