FLUORESCENCE IS DIFFERENT – it happens when subjects absorb light at one wavelength and emit it at another.
This isn’t a new discovery. Underwater film-makers and photographers have been recording the phenomenon for decades. Scientist Dr Charles Mazel originally developed the equipment and techniques for finding and recording fluorescence under water, establishing his Nightsea company to supply the sport-diving community with the gear needed.
Recently the California-based underwater compact lamp gurus Light & Motion have teamed up with Dr Mazel’s company to produce what they say is a simple solution for fluorescence-diving, the aptly named Sola Nightsea lamp. I took one with me to Indonesia’s coral-rich waters to see how it performed.

The Design
The Sola Nightsea lamp is based on Light & Motion’s standard Sola video lamps, utilising the same body, magnetic slide switching mechanism and battery-pack, but that’s where the similarity ends.
Ultra-violet light is generated from black-light LEDs and is supplemented by Nightsea’s propriety interface filter to trim the output and provide optimum performance.
The lamp has two beam modes: Flood, which employs six LEDs, and Spot, using a tighter cluster of three LEDs centrally placed in the lamphead. These give beam angles of 60° and 12° respectively.
Output is measured not in the lumens we know and love but in “Radiant Flux” (whatever that means). Three output levels are available in both Spot and Flood modes, with the shortest manufacturer’s stated burntime being 110 minutes on full power flood, and the longest 440 minutes when the lamp is set to its lowest output in Spot beam mode.
There is also an SOS flashing mode that’s standard on all the Sola lights.
The lamp is powered by a rechargeable li-ion battery that’s factory sealed within the body and uses external gold-plated connections for charging. A full charge takes around 150 minutes, assuming a fully discharged battery.
You’ll need to view and record images through yellow filters to actually see the fluorescence effect, and these are available as a mask filter, which sits over your dive mask, plus
a square filter that attaches to the front of your camera port and is held in position using bungee cords.
A really clever innovation, and one that places this particular lamp in a league of its own, is a removable phosphor filter that is clipped over the lamp-face. This transforms the blue UV light into a white light, enabling the lamp to be used as a standard diving torch
This is a useful addition that enables easy navigation and instrument-reading.
Various mounting options available from Light & Motion include a soft hand-mount, ball, Locline and YS mounts for camera systems and a pistol or T-handle grip.

Camera Set-up
For taking pictures my choice was a 60mm macro lens on my Nikon D800 DSLR. My strobes weren’t needed, with the only available light coming from the Sola’s blue LEDs, so they were left in the camera-room.
The 60mm would get me closer to my subject and reduce light fall-off issues. I used high ISO settings (1000-1600) to optimise exposures, allowing me to use faster shutter speeds and help reduce the effect of camera shake and smaller apertures to increase depth of field.
The lamp was positioned on top of the housing using a ball-mount system, and pushed forward to minimise the distance from the light source to my intended subjects.
The camera was set to manual mode with a starting shutter speed of 1/60th sec and aperture of f8. In manual mode I could adjust both of these settings individually as I needed.

Under Water
I took the set-up out on a number of night dives at Wakatobi Dive Resort in south-eastern Sulawesi. The lush coral reefs were a perfect hunting-ground for subjects that glow in the dark when placed under UV light.
The first dive was a revelation. Setting the Sola Nightsea on full-power Flood mode and placing the mask filter in front of my eyes, small patches of coral, anemone tentacles and crinoids literally popped out of the darkness, glowing a bright green as the UV light excited their fluoro-proteins. I really was seeing the reef in a totally different light.
When I located a subject to photograph, I found that the best results came when using the tighter spot beam and getting as close to the subject as possible.
For gauge and instrument reading the blue light was all that I needed, but to navigate
I found that a white light was best, so I clipped on the phosphor filter, turning the Nightsea into a standard torch as I finned from coral head to coral head.
I found reef fish that remained as dark as the night, giving off no fluorescence at all; others that had glowing stripes and nothing else; and lizardfish and shrimps that totally fluoresced and made fantastic glow-in-the-dark models.
The small animals seemed oblivious to my presence, and allowed me to get as close as I needed. The long burntimes allowed me to complete 90-minute dives with the lamp set mostly to its brightest settings.
A slide of the magnetic switch backwards swapped the beam angle from Flood to Spot, and subsequent slides forward increased the output through low, medium and high.
On my final night-dive the phosphor lens popped out and was lost. I didn’t notice this until I was back on the boat, by which time it was too late to try to retrieve it, and this was a disappointment. The filter is held in place by three little plastic hooks, and this arrangement was not secure enough.
The yellow camera filter worked really well on my large DSLR housing, covering the port with ease, but I think it may be a bit cumbersome on smaller compact set-ups.
The mask filter was quite distracting, because it’s a little narrow and didn’t cover my whole eye-line. I opted to leave it off after the first dive, recognising the lifeforms that would fluoresce by eye.
It’s easy once you get the hang of it, and a quick look through the camera’s viewfinder would confirm my assumptions.

Conclusion
This little gem was a joy to use – I can’t remember having as much fun on night dives before. I have used other UV products and witnessed the fluoro phenomenon before, but in my opinion this lamp is a game-changer.
The bright optimised UV output, long burntimes, mounting options and beam angles, coupled with the ability to switch to a white light with just the addition of a clip-on filter, places it firmly at the head of its class.
The price is a little off-putting, but if you manage to avoid losing the phosphor filter you could use the product as a standard dive torch as well, and optimise your investment.
The yellow filters are adequate but may not be suitable in all situations. A better option for DSLR users may be a screw-in filter fitted directly on the lens inside the housing.
If you are looking for something different to do on your night dives, “blue is the colour”.

SPECS
PRICES Torch £628. Mask filter £24. Camera filter £39
OUTPUT Radiant flux, 425-3000mW
DIMENSIONS 56 x 104mm
WEIGHT Just over 250g
CONTACT www.cpspartnership.co.uk
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