IN THE NOT-TOO-DISTANT PAST, our forbears were stumbling around in the dark with a simple flame from either a candle or an oil-lamp to light the way.
Lighting technology has moved a long way since those dark days (and even darker nights).
The electric light-bulb replaced naked flames at the turn of the 20th century and reigned supreme for nearly 100 years until an alternative to this incandescent light was found.
The breakthrough came in 1962 when scientist Nick Holonyak Jr invented the first visible-spectrum light-emitting diode (LED). Red diodes came first, followed by pale yellow and green. Then, in the 1990s, the blue diode was invented. This led to white LEDs, from blue diodes coated with phosphor.
Researchers then soon found that by combining red, green and blue diodes, white light could be produced. An LED revolution ensued, the new discovery being applied to traffic lights, flashlights, TVs and much else.
The past five years have seen the biggest evolution of the LED. The quest to reduce energy usage and greenhouse-gas emissions has seen substantial boosts in LED light output that also requires less energy.
Portable power technology has mirrored the LED’s evolution, with demand for batteries to power the latest electronic gizmos and gadgets such as smartphones and tablets leading to a reduction in physical size, and an increase in power output and the lifespan of reusable batteries.
All this new technology has naturally cascaded down to the portable lighting world, with smaller devices producing brighter light for longer and at lower cost.
It seems only yesterday that the only dive-lights available were used for one purpose, to see our way in a dark underwater environment. There was little choice of brightness level, and the holy grail was to get durations (burntimes) above an hour.
Battery-packs were, by today’s standards, huge, as were the torch bodies needed to house them.
Oh, how times have changed!

THE TESTS
Putting together a number of dive-lights to test proved a daunting mission. There are so many makes, models and genres, making them difficult to compare.
The obvious solution was to measure each one’s light output in lumens, but this proved more complex than expected, and it soon became apparent that I would need specialist measuring equipment costing tens of thousands of pounds (and a degree in lighting science), or laboratory facilities and a scientist to conduct the measuring procedure, which would cost almost as much.
So I settled on 25 lights, comparing each one by photographing the beams illuminating a white surface.
For consistent results I used a camera set on a tripod, in the same position and with the same settings throughout. The lights were positioned in exactly the same way. The resulting images are straight from the camera, with no post-processing other than preparation for printing.
The lights are ranked by price. The various functions of each one have been given a symbol so that they can be identified at a glance.

DIVE TORCH: A light that can be hand-held to light the way. Tight beam angles are the preference, because the narrow shaft of light cuts through turbid water without reflecting suspended particles and reducing the visible range (akin to driving in fog with the car’s main beam on).

FOCUS LIGHT: Modern digital camera focus systems rely on contrast in the subject to determine accurately the exact focus distance and return the sharpest results. A bright even light to illuminate the subject and increase the contrast can help the camera to focus. If an external camera flash is used, the torchlight is overcome and can’t be seen as a hotspot in the final image.

RED FOCUS LIGHT: Red light is almost invisible to species such as the shy mandarinfish but it still enhances contrast and allows the camera to focus. External camera flashes overcome the red light, leaving no trace in the final image.

VIDEO LIGHT: To capture vibrant true colours when shooting movie sequences, bright, wide-angle, constant light coverage of a scene is needed. Dull or bright hotspots will appear in the footage, so a smooth, even beam is essential. The wider the beam-angle, the more of the scene will be illuminated.

ULTRA-VIOLET LIGHT: Underwater flora, fauna and some marine animals give off fluorescent proteins when excited by an ultra-violet glow. To see or capture this fluorescence on camera, a yellow filter is usually needed for mask or lens.

FLASHING SOS LIGHT: The internationally recognised dot-dot-dot, dash-dash-dash Morse Code for SOS can be a life-saver if you’re ever in the unfortunate position of being lost at the surface or trapped under water.

FLASHING STROBE LIGHT: A bright flashing light is useful when visibility is reduced. It can be attached to a shotline or exit point to aid in navigating your way back to boat or shore.

STATE OF THE ART
The 25 lights featured here represent a cross-section of the marketplace. If a picture does paint a thousand words the beam photos tell the story, and, I hope, provide an accurate guide to the capabilities of each light.
Some have a specific task, others multiple tasks. I wasn’t surprised to discover that every light on this test produced a quality of illumination that outshone (pun intended) the lamps of yesteryear. You’d be hard-pushed even to find an underwater torch that uses halogen or gas discharge (HID) bulbs in stores nowadays.
Batteries have also evolved. Rechargeable lithium-ion units are almost standard fare, and are very reliable. Long life-spans and high outputs make them a viable option to factory-fit and seal into torch bodies.
I think USB-type chargers in tandem with sealed battery-packs are the future. Nearly everyone has a smartphone or tablet that uses a USB adapter, which means cutting back on spare batteries and charger hardware, especially when travelling.
The LED and battery revolution has been fast, total and overwhelming in the world of lights, and it’s still evolving.
Now there are rumours of aluminium air batteries that run for two weeks and are replenished by water. Imagine that, partnered with an LED that delivers 20,000 lumens of light – brilliant! Watch this space.


JARGON-BUSTER

Lumens (lm)
The unit of luminous flux is the measure of the total light output by a light source in every direction, corrected to ignore wavelengths not perceived by the human eye. Basically it’s the total amount of visual light generated by a source.


Lux (lx)
Lux is the unit of luminance, a measure of the intensity of light hitting a surface at a given distance. It’s equivalent to watts per square metre but corrected according to the human perception – it’s how much a torch (or other source) can light up a 1sq m area at whatever distance, usually quoted in the format “2000 lux at 10m”.


Candela (cd)
The unit of luminous intensity, or the light emitted from a source, has superseded “candlepower”, which measured luminance relative to the output of a candle of specific size and composition. As this is a measure of intensity as it leaves its source, it is unaffected by distance.


Burntime
The length of time the energy source powers the light is also known as the runtime, and is usually measured using the batteries sold with the lamp or recommended by the manufacturer. The runtime cut-off is defined as the moment when the light output is only 10% of its maximum.


Colour temperature (K)
The quality of light isn’t only about brightness but also colour temperature (measured in °Kelvin). To mimic the sun’s colour temperature (daylight), an artificial light needs to have
a colour temperature of around 5600°K. Cooler blue light has a higher Kelvin rating, and warm red light a lower one.



Mask-strap-mounted red light won't destroy night vision Hand-mounted light for reading instruments Hand-mounted UV lamp
Exposure Marine XS100-Red Night Vision & XS100-Blue Fluo Dive     £65
Functions: Hand- or mask-mounted night-vision or UV
Max output: 50 lm
Power levels: High, low
Beam angle: Not specified
Colour temp: n/a
Battery: CR123 rechargeable
Battery-level indicator: No
Stated burntimes: High 1hr, low 10hr
Switching: Screw-down head
Travel lock: No, requires battery removal
Material: Anodised aluminium alloy
Size/weight: 55 x 24mm dia, 39g
Depth rating: 100m
Contact: www.ultimatesports engineering.com

Notes: For mask-strap, head- or wrist-mounting. Red model useful on mask at night to illuminate instruments or camera controls. Supplied with spare battery and USB charger. UV Blue Fluo model requires yellow mask filter.
Tovatec Ultra III      £66
Functions: Hand-held dive-light
Max output: 500 lm
Power levels: 100%
Beam angle: 14°
Colour temp: 6000°K – 7000°K
Battery: 6 x AA alkaline or rechargeable ni-mh
Battery-level indicator: No
Stated burntimes: 6hr
Switching: Magnetic slide switch
Travel lock: No, requires battery removal
Material: Anodised aluminium
Size/weight: 226 x 51mm dia
Depth rating: 120m
Contact: www.tovatec.com

Notes: Suitable for primary recreational use or back-up technical dive-light
Tovatec IFL WA Zoom-R      £66
Functions: Variable-beam dive-light
Max output: 300lm
Power levels: One
Beam angle: 9° - 45°
Colour temp: 5000°K – 6000°K
Battery: 2x CR123
Battery-level indicator: No
Stated burntimes: 3hr
Switching: Magnetic slide switch
Travel lock: No, requires battery removal
Material: Anodised aluminium
Size/weight: 159 x 38mm dia, 238g
Depth rating: 120m
Contact: www.tovatec.com

Notes: Sliding-head sleeve with convex lens for zoom function. Removing sleeve increases beam angle for use with action-style video-cams. .
Dive Rite BX-1 LED      £80
Functions: Primary dive-light
Max output: LUX 12400
Power levels: One
Beam angle:
Colour temp: Not specified
Battery: 3 x AAA alkaline or ni-mh rechargeable
Battery-level indicator: No
Stated burntimes: 2hr with alkaline AAA, 4hr with lithium AAA batteries
Switching: Screw-down head
Travel lock: No, battery removal
Material: Marine-grade anodised aluminium alloy
Size/weight: 127 x 43mm dia, 200g
Depth rating: 150m
Contact: www.diverite.com

Notes: Can be used as primary recreational dive-light or technical back-up light. Comes with a wrist lanyard.
Scubapro Nova 700R      £89
Functions: Hand-held dive-light
Max output: 700 lm
Power levels: One
Beam angle: Not specified
Colour temp: 6000°K
Battery: Rechargeable li-ion polymer (LiPo)
Battery-level indicator: No
Stated burntimes: 2.5hr
Switching: Screw-down head
Travel lock: No, requires battery removal
Material: Anodised aluminium
Size/weight: 133 x 42mm dia, 200g without battery
Depth rating: 300m
Contact: www.scubapro.com

Notes: Suitable for use as primary light for recreational dives or back-up technical lamp. Comes with wrist lanyard.
Subgear Sector 5 LED      £109
Functions: Pistol-grip dive-light
Max output: 550 lm
Power levels: One
Beam angle: Not specified
Colour temp: Not specified
Battery: 4 x C cell alkaline or rechargeable
Battery-level indicator: No
Stated burntimes: 3hr
Switching: Trigger-style switch
Travel lock: Yes, mechanical lever
Material: Impact-resistant polycarbonate
Size/weight: 120 x 75mm excluding pistol grip, 700g
Depth rating: 100m
Contact: www.subgear.de

Notes: Smaller brother of Sector 7, which is powered by eight C cell batteries, has 700 lumens output and weighs just over 1kg.
UK SL4 eLED UV-395      £109
Functions: Fluorescence, spot
Max output: 500mW
Power levels: One
Beam angle: Not specified
Colour temp: n/a
Battery: 4 x C cell alkaline / LR14
Battery-level indicator: No
Stated burntimes: 10hr
Switching: Lever switch
Travel lock: No, battery removal
Material: ABS and polycarbonate
Size/weight: 157 x 60mm, head dia 50mm, 426g
Depth rating: 150m
Contact: www.uwkinetics.com

Notes: Standard UK SL4 dive-light fitted with optional UV-395 head that delivers ultra-violet light at a wavelength of 395 nanometres and doesn’t require yellow filters to view fluorescence effects.
£109
Light & Motion GoBe 500 spot      £145
Functions: Primary dive-light, focus light, SOS
Max output: 500 lm
Power levels: High, med, low, extended
Beam angle: 20°
Colour temp: Not specified
Battery: Factory-sealed li-ion
Battery-level indicator: Yes, single LED, green, yellow, red
Stated burntimes: High 1.5hr, med 3hr, low 12hr, ext 24hr, SOS 36hr
Switching: Sealed push-button
Travel lock: Yes, twist-lock at rear
Material: ABS polymer body, anodised alloy head
Size/weight: 122 x 45mm dia, 160g
Depth rating: 120m
Contact: www.lightandmotion.com

Notes: System light with platform compatible with six interchangeable light-heads including red focus, wide, search and UV Nightsea. Compatible with 25mm ball, lockline and YS-mounts. Charging via USB cable and gold-plated connections
Bigblue AL 1000XWP      £150
Functions: Action-cam video light, focus, SOS
Max output: 1000 lm
Power levels: 100 lm, 250 lm, 500 lm, 1000 lm
Beam angle: 120°
Colour temp: 6500°K
Battery: Li-ion rechargeable
Battery-level indicator: Yes, blue, green, red, flashing red
Stated burntimes: 100L 20hr, 250L 10hr, 500L 5hr,1000L 2hr
Switching: Multi-function push-button
Travel lock: No, requires battery removal
Material: Anti-corrosive anodised aluminium alloy
Size/weight: 127 x 39mm dia, 170g
Depth rating: 100m
Contact: www.liquidsports.co.uk

Notes: Compact light that’s suitable for GoPro-style action-cam use The light is supplied with removable red and yellow flip filters, wrist lanyard and mains battery charger. A two-arm camera tray, with ball fittings complete with two AL 1000XWP lights, is available as a system.
£150
Intova Action Video Light      £150
Functions: Action-cam video light, SOS, strobe
Max output: 640 lm
Power levels: Full, med, low
Beam angle: 120°
Colour temp: 6000°K – 6500°K
Battery: Rechargeable li-ion
Battery-level indicator: No
Stated burntimes: Full 2hr, med 3hr, low 4hr
Switching: Single multi-function push-button
Travel lock: No, requires battery removal
Material: Polycarbonate body, aluminium alloy head
Size/weight: 146 x 57mm dia, 179g
Depth rating: 60m
Contact: www.intova.net

Notes: Comes with tray and standard tripod screw for mounting Intova action video cams. Features slow and fast strobe flashing modes as well as SOS mode.
UK Aqualite-S 20      £155
Functions: Primary dive-light
Max output: 500 lm
Power levels: 100%, 40%, 15%
Beam angle: 20°
Colour temp: Not specified
Battery: Rechargeable li-ion, remove to charge
Battery-level indicator: No
Stated burntimes: 100% 1.5hr, 40% 5.6hr, 15% 9hr
Switching: Rear push-button
Travel lock: No, remove battery for travel
Material: Impact-resistant polymers with Hydralum head
Size/weight: 147 x 37mm dia, 396g
Depth rating: 100m
Contact: www.uwkinetics.com

Notes: Comes with tray and standard tripod screw for mounting Intova action video cams. Features slow and fast strobe flashing modes as well as SOS mode.
UK Aqualite Pro 100°      £246
Functions: Wide-angle SOS
Max output: 1200 lm
Power levels: 100%, 60%, 40%, 25%.
Beam angle: 100°
Colour temp: Not specified
Battery: Rechargeable li-ion, remove to charge
Battery-level indicator: No
Stated burntimes: 100% 1.1hr, 60% 2.2hr, 40% 3.3hr, 25% 12hr
Switching: Rear-toggle power dial
Travel lock: No, remove battery for travel
Material: Impact-resistant polymers with a Hydralum head
Size/weight: 127 x 37mm dia, 222g
Depth rating:150m
Contact: www.uwkinetics.com

Notes: Comes with 25mm ball-arm, swivel and fixed mounts for GoPro-style mounts, and USB/mains charger. Optional heads available for red, UV or spot-beam functions.
FIT LED 1200WSR      £250
Functions: Wide-angle SOS
Max output: 1200 lm
Power levels: 100%, 60%, 40%, 25%.
Beam angle: 100°
Colour temp: Not specified
Battery: Rechargeable li-ion, remove to charge
Battery-level indicator: No
Stated burntimes: 100% 1.1hr, 60% 2.2hr, 40% 3.3hr, 25% 12hr
Switching: Rear-toggle power dial
Travel lock: No, remove battery for travel
Material: Impact-resistant polymers with a Hydralum head
Size/weight: 127 x 37mm dia, 222g
Depth rating:150m
Contact: www.uwkinetics.com

Notes: Overheat function whereby smart electronics reduce light output to prevent damage if high temperature detected. 25mm ball-mount standard.
Metalsub XRE-1200      £250
Functions: Hand-held primary dive-light
Max output: 1200 lm
Power levels: 100%, 60%, 30%, 10%
Beam angle: 10°
Colour temp: 5700°K
Battery: Sealed LiFePo4
Battery-level indicator: Yes, LED green, orange, red, flashing red
Stated burntimes: 100% 100min
Switching: Multi-function push-button
Travel lock: Yes, remove rear cap
Material: Hard-anodised aluminium
Size/weight: 250 x 49mm dia, 480g
Depth rating: 250m
Contact: www.cpspartnership.co.uk

Notes: Supplied with MP1200 wireless contact-charging cradle with mains and 12V car-charger leads.
£250.
Inon LF800-N      £290
Functions: Spotlight
Max output: 800 lm
Power levels: Full 800L, low 300L
Beam angle:
Colour temp: 5000K
Battery: 3 x AA alkaline or ni-mh rechargeable
Battery-level indicator: No
Stated burntimes:
90min full, 265min low (Eneloop Pro batteries)
Switching: Rotary
Travel lock: Yes
Material: Aluminium alloy, rigid Almite
Size/weight: 145 x 60mm dia, 270g
Depth rating: 120m
Contact: www.inonuk.com

Notes: Comes with hand lanyard or can be mounted using YS-style adaptor. Also compatible with Inon screw-in colour filter or condensing lens sets. Tight beam said to be suitable for macro photography, giving snoot-style lighting.
Inon LF1100-W      £315
Functions: Wide-angle
Max output: 1100 lm
Power levels: Full, low
Beam angle: 85°, 95° with wide filter
Colour temp: 5000K
Battery: 3 x AA alkaline or ni-mh rechargeable
Battery-level indicator: No
Stated burntimes: 50min full, 235min low (Eneloop Pro batteries)
Switching: Rotary switch
Travel lock: Yes
Material: Aluminium alloy, rigid Almite
Size/weight: 127 x 48mm dia, 258g
Depth rating: 120m
Contact: www.inonuk.com

Notes: Supplied with hand lanyard or can be mounted using YS-style adaptor. Also compatible with Inon screw-in wide (pictured) or colour-filter lens sets.
Bigblue VTL 2800P      £325
Functions: Flood, spot, red
Max output: 2800 lm.
Power levels: Flood 100%, 50%, 25% and 10%, spot 100%, red 100%
Beam angle: Flood, red 120°, spot 10°
Colour temp: 6500°K
Battery: Rechargeable li-ion, remove for charging
Battery-level indicator: Yes – blue, green, red, flashing red
Stated burntimes: Flood 100% 1.5hr, 50% 3hr, 25% 6hr, 10% 15hr
Switching: Single multi-function button
Travel lock: No, requires battery removal
Material: Anti-corrosive anodised aluminium alloy
Size/weight: 140 x 55mm dia, 432g
Depth rating: 100m
Contact: www.liquidsports.co.uk

Notes: Overheat protection system. Mounting options include “hands-free” Goodman-style glove, 25mm ball, lanyard.
Bersub Variled 6X2      £345
Functions: Primary dive-light
Max output: 1600 lm
Power levels: 100%, 50%
Beam angle: 12°
Colour temp: 4300°K
Battery: 6 x AA alkaline or ni-mh rechargeable
Battery-level indicator: No
Stated burntimes: 100% 2hr, 50% 4hr (depends on battery type)
Switching: Watertight self-cleaning micro-switch
Travel lock: Yes
Material: Marine-grade anodised aluminium alloy
Size/weight: 130mm x 70mm dia, 550g
Depth rating: 300m
Contact: www.bersub.com

Notes: Patented safety valve for battery-gas discharge. Can be mounted to camera-arm systems with addition of 25mm ball, lockline or YS-adaptor for use as focus light.
Exposure Marine Sub M3      £350
Functions: Motion activated dive-light with flash and SOS
Max output: 1800 lm
Power levels: High, med, low
Beam angle: 20°
Colour temp: Not specified
Battery: Factory-sealed li-ion
Battery-level indicator: OLED digital display in hr/min
Stated burntimes: High 2hr, med 10hr, low 24hr
Switching: Combined capacitive and motion switching
Travel lock: Yes, motion-activated
Material: Anodised aluminium alloy
Size/weight: 113 x 47mm dia, 240g
Depth rating: 200m
Contact: www.ultimatesports engineering.com

Notes: No mechanical switch, responds to sequence of taps or rotary movement. OLED digital screen at rear displays output level, lock and battery time remaining. Charges via gold-plated two-pin contacts and USB cable with mains adaptor. Red or black, supplied with neoprene wrist-mount.
Bersub Variled 6 Neutral Wide 90      £360
Functions: Wide-angle video
Max output: 1600 lm
Power levels: 100%, 50%
Beam angle: 90°
Colour temp: 4300°K
Battery: 6 x AA alkaline or ni-mh rechargeable
Battery-level indicator: No
Stated burntimes: 100% 2hr, 50% 4hr (depends on battery type)
Switching: Watertight self-cleaning micro-switch
Travel lock: Yes
Material: Marine-grade anodised aluminium alloy
Size/weight: 130mm x 70mm dia, 550g
Depth rating: 300m
Contact: www.bersub.com

Notes: Patented safety valve for battery-gas discharge. Can be mounted to camera-arm systems with addition of 25mm ball, lockline or YS adaptor. GoPro can be mounted directly to handle.
£360
Tovatec Galaxy Video Light      £360
Functions: Wide-angle video
Max output: 2500 lm
Power levels: 100%, 50%, 30%
Beam angle: 140°
Colour temp: Not specified
Battery: Removable, rechargeable li-ion
Battery-level indicator: No
Stated burntimes: 100% 1hr, 50% 2hr, 30% 3hr
Switching: Rotating magnetic switch
Travel lock: Yes
Material: Anodised aluminium alloy
Size/weight: 112 x 70mm dia, 700g
Depth rating: 122m
Contact: www.tovatec.com

Notes: Comes with YS mount in hard foam-lined zip case.
£360
FIT LED 2500 Flare Video      £415
Functions: Wide-angle video, spot, red, UV, SOS
Max output: 2500 lm
Power levels: Three for wide, spot, red, one for UV, SOS
Beam angle: Wide, red, UV 120°, spot 15°
Colour temp: 5700°K
Battery: Rechargeable li-ion, remove for charging
Battery-level indicator: Yes, green, yellow, red, flashing red
Stated burntimes: At full power, wide 1hr, spot 2.5hr, red 5hr, UV 5hr
Switching: Twin buttons with battery indicator
Travel lock: Battery removal
Material: Hard-anodised aero-grade aluminium alloy
Size/weight: 125 x 50mm dia, 220g
Depth rating: 100m
Contact: www.uwvisions.com

Notes: Overheat function, YS-type mount standard.
Light & Motion Sola Nightsea      £565
Functions: Fluorescence, flood, spot
Max output: Radiant flux 3000mW
Power levels: High 3000mW, med 1500mW, low 750mW
Beam angle: Flood 60°, Spot 12°
Colour temp: n/a
Battery: Factory-sealed li-ion
Battery-level indicator: Yes – green, amber, red, flashing red
Stated burntimes: High 70min, med 140min, low 280min
Switching: Slide switch
Travel lock: Yes
Material: Impact-resistant polymers
Size/weight: 104 x 56mm dia, 254g
Depth rating: 100m
Contact: www.lightandmotion.com

Notes: Comes with phosphor filter that converts blue UV to white light, allowing use for navigation. Yellow mask or camera filter required to see or record true fluorescence effects.
Light & Motion Sola Video 3000 F      £645
Functions: Flood, SOS
Max output: 3000 lm
Power levels: High 3000 lm, med 1250 lm, low 625 lm
Beam angle: 90°
Colour temp: Not specified
Battery: Factory-sealed lithium-ion
Battery-level indicator: Yes – green, amber, red, flashing red
Stated burntimes: High 60min, med 120min, low 240min
Switching: Slide switch
Travel lock: Yes
Material: Impact-resistant polymers
Size/weight: 144 x 89mm dia, 265g
Depth rating: 100m
Contact: www.lightandmotion.com

Notes: Available with black or white (pictured) body colours.
Mounts include 25mm ball, lockline and ballistic hand-strap options.
Can be fully charged from flat in 1hr 45min via supplied multi-voltage 2A mains fast charger
Keldan Video 8X      £1335
Functions: Professional video
Max output: 10,000 lm
Power levels: Five from 28 - 105W
Beam angle: 110°
Colour temp: 5000°K
Battery: Removable li-ion 14.4V, 6.2Ah battery-pack
Battery-level indicator: Yes, LED display on battery-pack
Stated burntimes: 45 - 170min
Switching: Twist-ring on light-head
Travel lock: Yes, locks twist-ring
Material: Anodised marine-grade aluminium alloy
Size/weight: 235 x 72mm dia, 900g
Depth rating: 200m
Contact: www.keldanlights.com

Notes: Comes with polycarbonate female YS-mount adapter and mains battery-charger. Spare battery-packs £285