HISTORICALLY, DIVERS WHO NEEDED long burntimes, such as those who spent their time in caves, used a battery with a large capacity. This always came with a weight-penalty, so it seemed sensible to attach the battery canister semi-permanently to a gas tank or other part of the rig, so that its weight could be used as ballast, rather than having to add lead elsewhere.
The lamp-head itself could be quite small, but it needed to be connected to its power supply by an umbilical cable. Many such applications use a Goodman handle, which straps across the palm so that the lamp is mounted on the back of the hand, leaving the fingers free.
In the days of simple tungsten halogen lights, it was easy to compare the various technical diving lights available. The bigger the battery, the more power available, and the greater the wattage of the bulb, the brighter the light. With the advent of HID (High Intensity Discharge) and high-output LED (Light Emitting Diode) lamps, all this changed.
HID lamps take time to fire up to full brightness, and must not be repeatedly turned on and off, as this often causes them to fail.
They were originally developed for operating theatres, and some divers were disappointed at first to find that their expensive lights tended to be fragile in the hurly-burly of the diving environment.
However, HIDs do push out an amazing amount of light from what is almost a point-source, making efficient reflector design relatively easy.
Some produce a very cold light (at high colour-temperature) that penetrates water well but can be unsympathetic to its subjects.
Some manufacturers have answered the fragility problem by using special bulb-mounts designed to be shock-proof.
LED lamps do not have the ultimate light output of an HID, but they are virtually indestructible.
A false start occurred as some manufacturers failed to distinguish lux and lumens. A light source might push out a lot of lumens, but it is the lux that arrives at the subject that matters to the user.

AT FIRST REFLECTOR DESIGN WAS A PROBLEM, but this was solved in two ways. First, each LED was given its own individual reflector and focusing lens, arranged in clusters. This resulted in some lamp-heads being quite big in diameter to accommodate the required number of reflectors and lenses, but light output became quite respectable.
Now there is a new German light-emitting diode that has a remarkable output, and some lamp manufacturers are also offering this as a single LED source in a reflector without any lens, just like a conventional tungsten set-up.
Some manufacturers remain loyal to the conventional tungsten-halogen concept, and we include one example - the cheapest light here.
Rechargeable batteries are nickel-cadmium, nickel-metal hydride or lithium-based. Lithium gives most power in a compact form, but some questions regarding longevity and acceptability for carriage by airlines have yet to be answered.
At the moment the USA limits each passenger to a maximum of 25g of lithium content, so these batteries, when used, tend to be small.
Ni-mh batteries can be recharged safely at any state of charge without damage or memory effect.
Traditional ni-cad batteries require sophisticated (and sometimes expensive) charging electronics to avoid this, but some manufacturers still prefer this more traditional and perhaps predictable route.
Each test lamp was submerged, and we measured the brightness of the centre of the beam produced at a distance of 1.5m. We measured light delivered, rather than that produced at the source. The photos show the shape of the centre part of each beam, and attest to the evenness or lack of it.
Many of these beams were also accompanied by a bright peripheral halo, but the limitations of photography do not allow us to illustrate this.
Similarly, the light output measured is for direct comparison purposes here only. Remember, the human eye has an uncanny ability to adjust to make the most of what is available.
This is a side-by-side comparison only, and the lamps may give a different result when compared in air. Some are deliberately under-run (less light output) to provide better reliability and longevity.
That said, you are likely to think that your lamp is puny only if your buddy has a brighter one.
Thanks to a fluctuating pound and changing VAT, prices given are approximate.
All burntimes are estimated, and all prices include chargers (fast chargers where marked).

JMD A5070 Umbilical £308
As with any conventional tungsten lamp, this unit's 50W bulb gave a light that was much warmer in colour than any of the other more expensive technical diving lights tested here.
The nicely machined aluminium head has a milled ring that allows its focus to be adjusted for width of beam. Focused down to give the tightest beam, it offered a very bright oval cone of light but was rather patchy at other settings, giving a ring of light rather than a focused hotspot. It gave a huge, if very weak by comparison, peripheral beam.
The lead can be disconnected from the aluminium battery-pack, which works with a nice quick-release tank mount, and multiple batteries can be linked in series for longer burntimes if required. The price includes a fast charger.

DEPTH: 150m
COST: (inc. fast charger) £308
CONTACT: ww.jmdsports.co.uk

SCUBAPRO Module Light LED £439
Clearly made for Scubapro by GreenForce, this unit has a sleek Delrin battery-pack with pressure-relief valve that fits into a tank-mounted pouch, and an umbilical power cable running inside a pressure-hose and connected at each end by a screw-down, triple-O-ring-protected plug. This functions as the on/off switch, too.
Available with a range of alternative light sources, we tried the Module Light with the 9W triple LED head.
It produced a solidly even beam without much halo effect at comfortable daylight colour-temperatures. There are also HID, xenon, and IRC halogen alternative light sources available.
DEPTH: 200m
CONTACT: www.scubapro.com

SALVO Rebel 12 LED £595
This US manufacturer has a fiercely loyal customer base that will no doubt take to this latest offering encased in Delrin. This is a compact technical light that employs a single very-high-output LED devoid of any lens, combined with a battery-pack that is small enough to be stowed in a BC pocket or on a tank camband.
The lamp-head is switched on by screwing its two halves together (protected by two O-rings) and it is charged by unscrewing the lamp-head front completely to access the input socket.
A clip-on elastic palm strap is used in the same way as a Goodman-style handle.
The Rebel 12 gave a pleasantly graduated beam without any real hotspot, and a weak peripheral halo.
BATTERY: Lithium-ion 11V 5.2A
DEPTH: 125m
CONTACT: www.salvodiving.com

NITERIDER DeepStar Elite LED US $900
New this year, from the popular American manufacturer of compact diving lights, the DeepStar is a super-bright, long-lasting light.
It is machined in anodised aluminium connected via a lead broken by wet-connectors (with an electronic sensor to prevent shorting) to a little battery-pack that slips easily into a BC pocket.
The tiny lamp-head has a push-button with sequential switching to provide three different light output levels, plus a flashing locator beacon.
We found that it produced a very even wide beam with a very small hotspot.
Various mounting methods include the Goodman handle that is provided in the package, as is a fast charger.
BATTERY: Lithium-ion
BURNTIME: 3.5hr (full power)
DEPTH: 150m
CONTACT: www.niterider.com

METALSUB HID 126 Cablelight £642
The HID 126 Cablelight is made to a military spec from aluminium with an anodised Teflon coating for those with a military budget.
Metalsub lamps look like the sort of equipment you might find attached to an armoured car. This is a new model of the economy version, with a fixed clamp to its smaller battery-pack and a 24W HID lamp rather than the full nine yards of its bigger brothers.
The HID 126 Cablelight took a little time to warm up to full power but once it had it gave a beautifully even hotspot and a wide peripheral beam with a pleasant colour.
This light has the same locking magnetic reed-switch as its more expensive siblings.
BATTERY: Ni-mh 12V4A
DEPTH: 240m
CONTACT: www.cpspartnership.co.uk

HALCYON Explorer 10W Focusable £615
Superbly engineered in Delrin, with a robust internal battery pack that plugs neatly into the sealed lid of its canister, we had high hopes for this little head, with its beam angle varied by rotating a knurled ring at the back, and mounted on a Goodman handle.
We noticed a dark shadow of the bulb at the centre of the beam hotspot, and a peripheral beam in concentric rings when it was set at anything but the spotted down position where we tested it. This marred the look of the output, which was of high colour temperature (bluish) and took a few seconds to reach its peak.
The switch-on battery-pack meant that we mounted it switch-down on the tank for easy access. The lamp-head is permanently connected to the canister lid. A fast charger is included.
DEPTH: 152m
CONTACT: www.silentplanet.info

OMS Phantom 12W HID £675
OMS is one of America's leading technical diving equipment manufacturers. This compact lamp gave a very even if narrow beam at the high colour-temperature (6000°K) we have come to expect from a conventional HID.
It has a magnetic reed-switch on a head that is finished with a tough military-spec hard coating.
The rechargeable lithium battery is enclosed in a PVC canister attached via D-rings to a BC or hard backplate.
The umbilical cable is permanently wired with captured O-rings. Optional extras include a Goodman handle and diffuser.
Each individual lamp is pot-tested to 100m by the manufacturer before dispatch. Restart time is 5sec.
BATTERY: Lithium 12V 4A
DEPTH: 500m
CONTACT: Otter Watersports www.diverswarehouse.co.uk

FA & MI Special 150 £684
If you are a fan of LEDs, this one has more than most!
Eighteen 3W LEDs produce an evenly gradated cone of light over a wide area. Italian-made, the Special 150 is switched via an easily gripped rotating collar that operates a magnetic reed-switch, and it has three brightness settings for the choice of less light at greater duration.
The somewhat squat-looking compact aluminium battery canister hooks readily to any BC camband using a simple clip.
It's modular, so you can always dispense with the cable and back end of the lamp-head, screwing the battery-pack and head together to make a big, brutish-looking conventional diver's lantern.
BATTERY: Ni-mh 7.2V 5Ah
Burntime: 2.5hr (full power)
DEPTH: 200m
CONTACT: Cressi-Sub UK www.fa-mi.com

MB-SUB LED-Cave £720
A small German company makes this bijou lamp in anodised aluminium. It uses a novel system for switching by combining a magnet in a variety of detachable handles that operate a built-in reed-switch with two power settings.
The LED-Cave employs a solitary yet extremely high-output German-made lens-free LED to give light, with a rather small hotspot but a very even peripheral beam.
Once the lithium-manganese battery begins to lose a significant part of its charge, clever built-in electronics reduce the output of the lamp to emergency lighting levels, and automatically extend the burntime.
We used it with the Goodman-handle-style switch (included in the price).
BATTERY: Lith-mang (12.6V 9.6Ah)
BURNTIME: 6hr (full power)
DEPTH: 200m
CONTACT: www.mb-sub.com

OMS Phantom 7 LED £800
We first saw this new product lighting up the vast roof of the Las vegas Convention Centre during the DEMA trade show.
The Phantom 7 is so new that very little technical information was available for this large-fronted multi-LED lamp.
However, its light output seemed phenomenal, with a strong even hotspot and a very wide peripheral halo. This comes courtesy of seven well-spaced individual LEDs with
large lenses.
The magnetic reed switch is on the head, and the battery arrangements appear to replicate those of the 12W HID Phantom, with a compact lithium battery in a permanently cabled PVC canister.
A bigger battery for a longer burntime may be available later.
BATTERY: Lithium 12V 4A
DEPTH: 500m
CONTACT: Otter Watersports, www.diverswarehouse.co.uk

The Dual Pro offers variable output in three stages, between a single 10W to twin 14W outputs of its two HID lamps, all controlled by a four-position switch on the lamp-head connected via a lead with wet connections to a tank-mounted battery with its own switch.
This combines to make it a very versatile lamp. At our test distance it gave large and nicely overlapping hotspots, and an excellently wide and bright peripheral beam.
Various mounting methods include a novel head-mount for totally hands-free use.
Made of composite nylon and glass-fibre, the Dual Pro HID II is this US manufacturer's latest and top product. A fast charger is included in the price.
Niterider lamps have found great favour with US cave-divers.
BATTERY: Ni-mh 13.2V 4.5A
BURNTIME: 1hr (full power)
DEPTH: 150m
CONTACT: www.niterider.com

METALSUB HID 200 Cablelight £915
Metalsub lamps are made in the Netherlands to the highest military specifications.
You would probably be gutted if you paid out £915 for this lamp and it wasn't the brightest on the dive, but it won't let you down.
It also delivered its beam at a friendly 4200°K colour-temperature.
We found that it gave a slightly uneven hotspot, but a huge peripheral halo. With three power settings to extend the burntime to more than three hours at the lower outputs, and an indicator LED system on the large lamp-head to reveal the state of charge, it uses the same robust HID arrangement as the German automotive industry.
The battery canister is big, but it has a great precision-built quick-to-connect battery tank-clamp.
BATTERY: Ni-mh 12V 9A
BURNTIME: 2hr (50W setting)
DEPTH: 240m
CONTACT: www.cpspartnership.co.uk

SOLUS SU1250 LED £950
With six close-spaced, high-output LEDs in a robust aluminium head (the Goodman handle is included in the price but optional), this Irish-made lamp has two power settings operated by a collar that rotates around the lamp-head, in conjunction with an internal magnetic switch.
It gave us a big, even and sharply focused beam without any real hotspot or much peripheral halo.
The permanently fitted cable is designed for use in other submarine applications to 1000m. The tough aluminium battery canister is charged by external connections via an intelligent charger, so that it never needs to be disassembled by the user, and a pressure-relief valve takes care of any gases produced.
The battery pouch can be fitted to a tank camband or the D-rings of a BC.
BATTERY: Ni-mh 5Ah
BURNTIME: 2.5hr (full power)
DEPTH: 200m
CONTACT: Solus Submersible Products, www.ssp.ie

HALCYON EXPLORER 21w HID Focusable £975
Halcyon lamps are beautifully made to give pleasure in pure ownership alone, and this is probably the company's most popular lamp, despite its high price. It has a relatively large lamp-head with a lead permanently connected to the lid of the canister.
A simple sliding mechanism allows the bulb to move to and fro (with screw lock) within an open-style "wet" reflector that lets the user vary the beam angle.
We found that the Explorer took some time to reach working brightness, and there was a dark spot in the centre of the beam when set to wide, but at the narrow setting it certainly penetrated the water well.
An enormous high-tech charger includes a cooling fan. The Goodman handle is standard, and the price includes the fast charger.
DEPTH: 152m
CONTACT: www.silentplanet.info

These Belgian-made lamps comprise a completely modular system with alternative power sources and lamp-heads.
The lamp-heads can be used directly connected, or with an optional umbilical cable encased in a pressure hose and in conjunction with a simple wrist mount if required. Every component is fully interchangeable.
Batteries are inevitably ni-mh, and we used the popular Delrin-encased F2 battery-pack, depth-rated to 350m, for this test.
Thevarious GreenForce anodised aluminium lamp-heads shown here give a good demonstration of the performance of the different types of light generally available.
Each is switched on by screwing down the lead connection of the umbilical at either battery or lamp-head end. Each end is triple-O-ring protected.
Sequential switching of the LED models allows you to dim them in two stages from full output for added burntime, plus for use as a beacon and in SOS-flashing mode.

The most recent development of its best-selling combination, this GreenForce three-LED lamp produced an eerily even beam, without any peripheral halo or any discernable hotspot.
BURNTIME: 3hr (full power)

An evenly focused tight beam of light with a neat hotspot in the centre and a very minimal peripheral beam characterised this lamp, with its solitary very-high-output LED. It did not project a huge amount of light, but it was very useable.
BURNTIME: 2hr (full power)

This new compact HID lamp produced a very bright light in a tightly focused beam, with little if any peripheral effect.
BURNTIME: 150min

A cluster of four focused LEDs produced a very soft, broad and evenly distributed beam of light that covered a large area.
BURNTIME: 2hr (full power)

Known to be robust, this lamp gave a good even hotspot in a tightly focused beam, at a high colour-temperature. The beam was cool and penetrative.

The front glass is rather massive to accommodate nine LEDs, each with its own lens and reflector. This unit produced a broad and even centre and incredibly even peripheral 90° beam.
BURNTIME: 80min (full power)

GREENFORCE QuadriStar £568
GREENFORCE MonoStar £552
GREENFORCE NonaStar £747
Contact: Lumb Bros, www.greenforce.co.uk