Other lights

Beam Quality
8 / 10
8 / 10
Battery Life
7 / 10
6 / 10
Value for Money
9 / 10


Underwater Kinetics Light-Cannon-100.
38 / 50
One of the most technologically advanced diving lights on the market but just as home on dry land as it is at depth, the Underwater Kinetics Light-Cannon is the first hand-held light on the market to utilize the Welch Allyn "Solarc" miniature metal-halide HID lamp. Just 10 watts of power pours out as much as 450 lumens of cold light as white as the sun. The cold blue-white "daylight" tinted light carries further under water than regular incandescent lamps do, and the natural colour makes it ideal as a video light.

Underwater Kinetics Light-Cannon-100

Manufacturer`s Web site-
Buy yours from- many places that sell specialist lights and diving equipment.
Cost- US$170-175 (price may vary depending on supplier)

Size- size.
Lamp type- Welch-Allyn 10 watt short-arc metal halide.
Body colours/finishes- Black.
Batteries- 8x "C" 1.5 volt or optional rechargeable pack.
Switch type- Side-to-side Trigger.
Waterproof?- Yes, but not sure how deep.
Approximate beam half-angle- ~6 degrees.
Peak Beam Intensity- not yet measured.

Notes- Two handle options are avaliable- a conventional lantern-style and (as tested) a pistol-grip. Also note that the Beam Profile pictures below were not all taken at the same exposure setting- the "normal" shot is at a lower exposure to the two with wide angle filters fitted.

Beam Profiles...
Light-Cannon Beam Profiles

My light came in a plain brown cardboard box without so much as internal padding or supports, but I understand this is not normal. This unit under test was sold with the name "Instructor Team" printed on top - I don`t know exactly what this means but presumably it was branded for sale by another company or dealer and asides the no-frills packaging, doesn`t differ from "regular" ones. As it was, the box contained the light, a pistol-grip handle and not one but two packs of wide-angle filters and instruction sheets. I can only imagine this was a mistake! From what I`ve seen, the regular package you`d buy in the stores also includes the lantern grip handle, and is printed with Light-Cannon graphics too. I`d guess there`s some sort of inner packing too. The manufacturer reccomends that the light is shipped complete with batteries so it is likely yours will come ready to go. My vendor ignored this advice and placed an X-shaped corrugated card spacer inside instead. The ballast/lamp/reflector module will slide up and down inside the body when empty increasing the risk of damage in transit, so at least they had the sense to put something in there.

Expanded view showing the partsA lot of light requires a lot of batteries - 8 of them, alkaline C-cells. A rechargeable option is also avaliable - the light can be purchased complete with charger and battery pack, or the charger and pack can be purchased as an accessory if you`ve already got the light. I havn`t had the opportunity to try this rechargeable system out so unfortunately can comment no further on it. As mentioned, it is likely you`ll have the batteries supplied pre-installed but sooner or later you`ll need to replace them, or if like me, you`re unlucky and have to go buy and fit your own before you can start dazzling yourself with this thing!
To install the batteries, begin by unscrewing the head section. Ridges moulded into the rubber cover help you grip it - and it can be quite stiff if it hasn`t been removed for some time. Take care when removing it as unfortunately the reflector is loose and might fall out - it`s best to keep it upright for now. Lift out the reflector and bulb/ballast module, and now you can tip out the used-up batteries, assuming that`s what was in there to begin with. The base spring/contact plate will come out too but don`t worry as it`s meant to. Before inserting the new batteries you`ll need to drop that bit back inside. Look closely at the contact side - you`ll see the marking "Align here". Look inside the body of the light and you`ll see a white sticker printed "Align Here" too. You need to ensure these alignment marks are on the same side, so the plate goes in the right way round of course. Holding the body preferably at a slight angle, drop the correctly aligned plate in there, springs-first. Although it fits only loosely and might seem like it could flip over or get stuck on its way down, I have found this is not normally the case. Should it get disoriented however, just tip it out and try again. Once that`s in place you can insert the batteries.
Getting them in is not the easiest thing to do, since there`s quite a lot of space inside for them to fall over, slide to the wrong corner and generally be a nuisance. There`s no markings in the battery compartment or on the ballast assembly indicating which way round - you just have to remember that they go in with the flat negative ends facing the wider oval shaped contacts. It`s designed so they won`t actually make contact if you get any the wrong way up. To get them in, it`s best to tilt it with one corner facing you, then slide the first two batteries down in that corner. Then you can slide the ones either side of that pretty easilly and the last two go in easier still. Careful not to bump it or tip it too far either side until they`re all in. Once filled, drop the ballast/bulb/reflector part in - it only fits one way round - and screw the head back on. Done!
Battery life is quoted as 3-4 hours with alkaline cells. A continuous graphed burn test has not yet been performed - given the high cost of those cells in this country - but I will conduct one as soon as resources allow for it. The results will be noted below in the Long Term section. I have, however, already used up one set of cells during casual use - and offhand I reckon it at least lives up to the 3 hour claim. We`ll see....

Welch Allyn Solarc 10 watt metal-halide lampThis light uses no ordinary bulb! Look inside and you`ll see something rather special - the smallest Metal Halide HID lamp in current production in the world today! The tiny 10 watt Solarc to be precise - a recent innovation from speciaist lampmakers Welch Allyn. Inside it, 450 lumens of cold icy blue-white light pour out of a space smaller than a grain of rice (see the macro shot below) - over 3 times as much as a properly driven 10 watt Xenon-Halogen lamp, the most efficient kind of filament lamp currently avaliable. No other portable white light source currently beats this in the power and efficiency stakes. It is bright! Very bright!
Extreme close-up of the arc gap in the little lamp. The distance between the 2 electrodes is less than 1.5mm!All that technology comes at a price though - replacement lamps for the LC100 clock in at around US$60 minimum, and are usually near $85! The life is up there with decent household incandescent lamps though - typically 1000 hours. A whole lot longer than small Xenon/Halogen bulbs that dive lights typically use, and is a whole lot of run-time for any flashlight anyway, especially given the fact that it runs no longer than 4 hours per set of 8 batteries. In theory replacing the lamp shouldn`t cost you all that much compared to a "regular" light, as you won`t have to do it very often. I say in *theory* though as there have been reports that these tiny little bulbs are quite fragile. Drop a 1000 hour bulb hard enough and it`ll break just as easy as a 10 hour bulb - only this time you have to cough up a premium price to replace it. Since this reviewer can`t afford to find out exactly how fragile it is, right now I can`t say if the claims are true. I have bumped it a few times though - but more on that later.
Anyway, whenever and however the time comes that it needs a new lamp, changing it is not hard. Paying for the replacement might be, but at least fitting it is easy enough. Do it by simply unscrewing the bezel, lifting out the silvered reflector, grabbing hold of the old bulb and carefully pulling it free of the socket. A slight side-to-side movement is enough to ease it free - it`s firm enough to stay put if bumped but not hard to get out when required. Once free, dispose of safely and grab hold of the new one. Align the two pins with the holes making sure the tab round the black plastic base lines up with the notch in the white silicone-like shock absorbing material round the socket, and carefully push it down in place. The pins are short and sturdy, hard to break off if you don`t get it quite right and have to wriggle it round a bit. Take care and you`ll find it goes in easilly. That done, replace the reflector and screw the head back on. Finish by operating the switch to confirm it works again.

Common to many other Underwater Kinetics dive lights, this one has a lockable trigger style side-to-side switch. With the pistol-grip handle fitted, it`s conveninetly located right in front where a trigger should be, and is quite easy to use. Side-to-side trigger switch with lockout featureThe switch is in two parts - the main body and a captive "lockout cap" which can be pulled out and in with a snap-action - as shown to the left. When out, the switch can be moved to turn the light on or off, but when pushed in, the trigger remians locked to prevent unwanted activations or de-activations. The last thing you want is your light going out by accident when you`re 50 feet underwater, at night!
To operate it, first move the locking "cap" to the Out position - raised away from the body of the light. This can be easilly accomplished while still holding the pistol-grip handle, and using just one finger. You might like to curl your thumb round for a bit of assistance though if it seems a bit stiff. Then, turn the switch round to the right (with the bezel facing away from you) - and the ridged sides of its largely triangular profile help aid your grip somewhat. For example, if you`re holding it in your right hand, you want to pull it with your index finger and push with your thumb if desired too. The light will strike and run up to full brightness in about 20 seconds. When on, pushing in the lock-out cap again will fix the trigger in place so it can`t be turned off easilly by accident.
To turn off, ensure the lock-cap is out and turn it the opposite way. Holding it in my right hand I find it a little tricky to accomplish without assistance - it wants to be pulled with my thumb and pushed with my finger but the shape and orientation doesn`t make this so easy to do - I have to alter my grip slightly to do it - either one way to extend my thumb or the other way to curl my finger round it. Not impossible of course - and in fact if you use your middle finger to operate the switch it makes it a lot easier.

The pistol-grip handle offers a secure method of holding and pointing the light in the right direction. It has been designed to fit the hand comfortably and I expect it would be no bother to use it continuously for hours. That is, if you don`t take into account the significant mass of the body! It`s big and full of C cells, not to mention the ballast/lamp holder assembly which is partly made from cast aluminum. This does tend to make it feel top-heavy when used on dry land. The good news is that the handle is positioned such that the balance is good - it doesn`t want to lean off to one side or the other. Also, it must not be forgotten that the primary aim for this light is diving - used underwater the buoyancy offered by air trapped inside should lessen its weight making it much less unwieldy - however I am not able to test it in such an environment so cannot say for sure.
For dry land usage, there is an optional lantern-grip handle as mentioned previously. This changes the grip from an underhand top-heavy orientation to an underhand, more traditional grip that is said to be much better to use. Again though, I havn`t had the opportunity to try this one out yet - but will hopefully be able to do so sometime in the future.

If you havn`t experienced the light output of a short-arc HID lamp, you`re in for a surprise. When you first activate it, you would be forgiven for feeling dissapointed. It will light almost immediately but to begin with, the light output is very dim and kind of orangey. But, watch for only a few seconds and it transforms - fading from a flickery orangey-blue, through a colour that is similar to that of those blue flourescent "bug zappers" and stopping at a dazzling blue-white that comes close to that of daylight. And all the while it keeps getting brighter and brighter. It reaches full power after about 20 seconds, and full power is very impressive indeed. The following sequence illustrates this run-up sequence. Please note that the middle 2 shots do not accurately depict the colour - it is bluer during these phases than shown.

Run-up sequence, total time from start to finish is under 20 seconds

The beam quality is generally good - smooth with no dark spots. It has a distinctly noticeable sharp hotspot surrounded by a bright, smooth corona. There is a fair amount of side-spill too. Unfortunately despite its power it does not throw extremely far. Up to a couple hundred feet it`s OK but becomes very diffused much beyond that. It`s not designed to be long-throwing though but rather as a close to medium-range video flood light. Two supplied diffusing filters re-inforce that fact. These can be fitted to spread out the light making it better suited for close work - you can see their effect in the beamshots above.
One thing I did notice is the fact that the reflector is loose inside the head and has a degree of movement which affects the beam. The bulb itsself can move too - due in part to the shock-resistant mounting. Often I can screw the head back on and find that the beam has become somewhat off-center and distorted. Fiddling with the reflector and bulb will restore it to its original, centered state - but in a light this expensive I did expect better. It`s not a catastrophic flaw but it would be better if the reflector had a more secure mounting method than just resting it over the end of the ballast and using the pressure of the head to keep it in place.

The Light Cannon is extremely well-made. Its impact resistant body (possibly ABS plastic) is moulded as just one piece which has thick walls all round, and the head - which could be Lexan or polycarbonate - is also very thick with additional "armoring" in the form of a rubber shroud over the outside. Incidentally that shroud serves a second purpose of preventing sideways glare. There are two "dovetail" mounting points for the solid moulded handles, these appear to be very sturdy too. Since the only Lanyard attachment points is on the handle, you would want the attachment points for the handle to be as strong as they can be because if they fail, the big expensive body of your light will sink like a stone. In deep water, if that happens it`s gone forever :( . I think it would be better to have the Lanyard attach to the body, but the design doesn`t really lend itsself too well to that option. the white stuff round the bulb socket is silicone - to protect the bulb from shocksAll in all though, the physical construction is first-rate. However inside.....
I have heard many people say that the tiny metal-halide bulb used in this light is much more fragile than the usual halogen and Xenon lamps used in other dive-lights. And despite the tough construction of the body, the Light Cannon doesn`t survive drops onto hard surfaces very well, for that reason. Personally I havn`t found this to be true yet - but since I purchased this one with my own money, I have probably treated it quite gently as I know I couldn`t really afford to replace it. That said, it has seen its share of bumps and knocks, even when lit. It fell off the bed to the floor below (OK, less than 2 feet but onto solid, bare wood) without consequence. The fact that it has a fair degree of integral shock-isolation round the bulb`s socket, and the fact that the bezel is well protected with a thick rubber cover says that UK have taken into account the fragility of the tiny, costly bulb and have done their best to protect it. Again, remember the primary intended users for these lights - divers. Traditionally divers take very good care of their equipment since their life often depends on it (and most of it costs more than a Light Cannon) so they`re unlikely to let it drop any significant distance that easilly. Just be careful, and it`ll serve you well, I`m sure of it. And don`t forget to use the Lanyard!

Long term testing.
As I come to finish this review, I have had the Light Cannon in my posession for almost a year. During that time it has seen a fair bit of use and has burned through one set of batteries. More recently while writing this review I had to remove the head several times - this was about 3 weeks ago at the time of writing. I found it hard to remove at first but put that down to the fact that it had been so long prior to then that it was last opened, and there probably was no lubrication on the o-ring and threads. Well, today while finishing things off and attempting to take one more photo of the innards - to show the shock isolation round the bulb socket - I attempted to remove the head once more. Only this time it wasn`t interested in budging. Trying to use the handle as a lever to aid my grip was futile - infact the force I had to exert was enough to break the handle free of its dovetail mounts. Seems they aren`t quite so sturdy after all - though probably plenty enough to survive most normal use. This is not normal use.
With nothing left to lose, I clamped the body of the light in a bench-vice and again tried to free the head. My first attempt at this was just as hopeless, and the forces I was exerting had left my hands sore. The rubber cover of the head began to rotate but the head itsself was stuck fast. I left it so my hands would stop hurting so much, and came back to it later on. Wrapping a towel up so it was very thin, then wrapping this tightly round the head, made for an even better and more comfortable grip. A combination of turning and pulling on the free end of the wrapped-up towel finally got it free, to my relief.
It would seem that the o-ring or threads themselves were causing the stickage - and this time it`s not down to a lack of lubrication. I cleaned the threads and o-ring, and applied some Super-Lube the last time the head was off. Very possibly though, I used too much lube - which can be as bad as not having enough - so in the hope that it would prevent further problems I cleaned off all but a slight trace and re-fitted the head (after taking the photo above). Not too tightly either. We`ll see if it happens again or not.
I consider this to be a serious fault of this particular light. I am not sure if it`s an isolated incident or whether it`s something many people have experienced but either way it`s bad. Away from tools the top could get stuck fast making it useless if the batteries can`t be changed when required. You obviously have to be careful as to the type and amount of lubrication to apply to the o-ring, and also be aware of how hard you tighten the head... :( .

Updated - March 15th. I have recieved several responses to my stuck head predicament following a posting at Candlepower Forums - many thanks to all who`ve replied. It is apparently not an isolated incident, could arise from the design of the light but probably arises mainly from things I did. The first and most probable cause is the type of lube I used on the o-ring and threads. Apparently some types - petroleum based especially - cause o-rings to swell and dramatically increase friction. They can also dry and harden somewhat on plastic threads, acting like glue. The correct type of lube to use on this and any dive-light is Silicone Grease which is avaliable at all good diving stores. Additionally it is not reccomended to tighten the head excessively - it should be enough to cause slight compression of the o-ring but not so much as to squash it flat. That`s a guaranteed way to cause your head to sieze.
Finally it could have been caused by differential pressure. Meaning, that the pressure inside the light was noticeably higher or lower than the pressure outside, with no way to equalize because of the waterproof seals. This could be caused by differences in the weather - temperature and humidity changes between now and the time the head was last re-fitted. It could also be a result of outgassing of the batteries, but platinum catalyst pellets inside the ballast module (I forgot to mention those before!) are supposed to absorb the hydrogen gas normally emmitted by batteries. It`s still a possibility.
Regular maintenence, use of the proper lube and not overtightening will all help to prevent the heads of any dive-lights from sticking like this.

Assuming the head doesn`t stick again in the future, and assuming time and resources allow for it too, a graphed battery life test will be conducted. Any other updates worthy of being mentioned, will be noted here.

Summary and Conclusion.
...still to come.

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