The Design
The Keldan Video 8X is powered by a removable 14.4v, 6.2Ah li-ion battery-pack. An eight-segment green LED display on the rear shows the battery state of charge at a glance.
It takes three to four hours to charge the cells from empty, depending on the input voltage and ambient temperature. Once fully charged the battery will give claimed burntimes of between 45 and 170 minutes depending on the power-output setting.
The light source is a latest generation LED with a claimed maximum output of 10,000 lumens, delivered at a colour temperature of 5,000° Kelvin. The light has five power settings ranging from 28 to 105W, and these are accessed via a twist control-ring behind the head of the lamp.
A convex acrylic lens spreads the light evenly over a 110° beam angle under water and softens it, giving extremely smooth speckle and hotspot-free coverage.
The main body is built from marine-grade aluminium alloy and anodised in a purple colour. A transparent plastic, screw-in end-cap gives a clear view of the battery indicators and is double-O-ring-protected, giving the lamp a depth rating to 200m.
The on-off ring is protected from accidental operation by a locking button that needs to be pressed and moved to allow the ring to turn.
Colour Rendering Index
The science of light is a complicated subject. I really don’t understand it, nor do I need to. What I do need to know are the things that affect my photography and video shooting; especially if these can help me improve the outcome. Let me share the few things that I do know.
The quality of light isn’t all about brightness; it’s also about colour temperature (measured in °Kelvin).
The sun’s colour temperature varies throughout the day, month, year and at different locations from between 5000°K and 6000°K. In the motion-picture world the colour temperature for artificial lighting to mimic daylight is standardised at 5600°K.
The quality of light generated from video and photo lamps can be measured using the Colour Rendering Index (CRI), which indicates a lamp’s ability to render colour accurately, with a rating of 100 at the top of the scale.
CRI is actually a measure of the quality of colour light as established by the International Commission on Illumination.
A CRI rating of 82, that of the Keldan Video 8X light, will allow your eyes and cameras to capture colours that are much more accurate than those shot with a rating of, say, 70.
Lights with a rating of 75 and below can produce substantial colour shifts, loss of saturation and resolution.

Under Water
The lamps have clip-on, high-impact polymer mounts with “YS” connection. These allow them to be mounted on a 30cm ball-and-arm system, giving an almost infinite choice of position in relation to the camera’s focal plane.
I mounted two lights on my Nikon D800 Subal, set up with a wide-angle 15mm Sigma lens behind an 8in dome-port. I’ve recently seen some pleasing footage captured using tight macro lenses, but the Holy Grail for me has been beautifully lit wide-angle video, a challenging task for any external lighting combination.
The first thing I noticed when I powered up the lamps under water was the smooth coverage they delivered. There were no signs of hotspots or poorly lit sections in the central areas, and the edges of the beam gradually faded away to leave an inconspicuous drop-off in illumination.
Twin lamps gave me total coverage of my subjects at a distance of about a metre. This equates to large sections of reef as seen through my 15mm fisheye, all perfectly lit without harsh shadows to reveal sponges, hard and soft corals in their natural vibrant colours.
I found that by reducing the output of the lamp on the opposing side to the sun I could create natural-looking footage. The Keldan 8X’s extremely high outputs allowed me to “stop down” my aperture while shooting directly into the sun to prevent that horrible burnt-out and totally clipped white blob, yet I could still perfectly illuminate the subject in the foreground.
I found the burntimes sufficient, with the batteries lasting for two full dives, capturing around 40 minutes of top-quality footage.
The green charge-state indicator LEDs proved to be accurate and a useful tool to assess how much time was left before the batteries needed to be recharged or changed.
The batteries are interchangeable and can be purchased separately, so fully charged spares can be exchanged between dives if the need arises.

Conclusion
My area of expertise lies in underwater stills photography. I’m very new at capturing video – so new, in fact, that I had to do some serious cramming with my camera’s instruction manual before this trip to learn how to use the movie functions properly.
The footage I captured isn’t going to have the likes of John Boyle or the guys at the BBC Natural History Unit quaking in their boots, but to me it appeared beautifully illuminated with vibrant, natural-looking colours, and without those harsh shadows that can sometimes ruin the effect.
Daniel Keller has produced a product that’s used by many of the world’s professional underwater videographers to bring us the jaw-dropping footage needed to meet our modern entertainment expectations.
Having used them I can see why – they’re underwater lighting perfection personified.

PRICE £1335, spare battery-pack £285
SIZE 23.5 x 7.2cm diameter
WEIGHT 0.9kg dry, 0.32kg wet
BATTERY 89W, 14.4V, 6.2Ah li-ion
LIGHT Flux (max) 10,000 lumens, 4300 candela
LIGHT Flux (min) 3200 lumens, 1400 candela
COLOUR TEMPERATURE 5000°K, CRI-82
MOUNTS Polycarbonate, YS
CONTACT www.keldanlights.com
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