July 2001
By John Francis

Lights Reviewed in This Article

||| |---|---| | Ikelite RCD Super 8 Pelican Nemo Pelican Aqua King Princeton Tec Shockwave | Underwater Kinetics Light Cannon Underwater Kinetics Sunlight C8 Underwater Kinetics Sunlight D8 |

Want a Really Bright Dive Light?

|| |---| | | | |

You can tell how bright a dive light will be by how many batteries it contains about as well as by any other measure. Here's why:

• All conventional disposable batteries from AAA to D have the same voltage, about 1.5 volts each. (The size mostly affects how long they last.)

• All the dive lights that use those batteries connect them in series, which adds up the voltage (except one light, the Princeton Tec Surge).

• Voltage is one of the most important determinants of brightness.

So eight batteries provide about 12 volts and, potentially at least, the brightest light. Six batteries give 9 volts, four give 6 volts and two give 3 volts. Voltage is not the only factor that determines brightness, but it is a rare four-cell light that is as bright as one with six.

Four- and even two-cell lights may be adequate for night diving in clear water, especially if there's a moon out and you're with a group. But sooner or later, you're likely to want something bigger. This month, we review seven 8-cell lights from four of the five dive light manufacturers. (Other lights are available, often manufactured offshore and sold under familiar scuba brand names. I've yet to see one that tested even close to these.)

Rechargeable battery packs are a whole different story, of course. Popular with tech divers in particular, they can provide a lot more power and brightness, but are generally bigger and more expensive, and require careful maintenance. We'll look at them another time.

How Bright Is It?

The number of batteries is just the beginning of the story, because 8-cell lights differ considerably. Manufacturers can drain the batteries faster for more power to the bulb and produce more wattage. But bulbs differ in how efficient they are at turning power into light. The difference between HID bulbs and incandescent bulbs is the most dramatic, but even incandescent bulbs vary noticeably. And often there's a trade-off with bulb life too: You can "overdrive" a bulb to make it brighter, but it will burn out sooner.

The reflector is an even bigger factor than the bulb in determining what comes out the end of the light. One reflector might concentrate nearly all the illumination into a tight beam, giving a tiny, brilliant "hot spot," while another spreads the same amount of light over a wider, but dimmer area. The reflector is a lot like the nozzle on the end of a garden hose, capable of forming the same amount of water into anything from a tight jet to a wide spray.

Which Beam Do You Want?

Most people shop for lights by shining them at the ceiling and picking the brightest one--the brightest hot spot. So light manufacturers, no fools, tend to concentrate as much light in as narrow a beam as possible. But you don't use a dive light for picking out a street sign at long distance. You're more likely to want to illuminate a broad area at fairly close range, though you may also want to look far back into a dark cave.

Probably you want a compromise: a fairly large, but fairly bright hot spot with fuzzy edges and a gradual drop-off so there is still usable illumination over a wide area. You also want a uniform, featureless pool of light. Sometimes the hot spot shows patterns--often the shadows of the filament itself. When you paint these shadows on the reef it can be hard to tell what is real and what is illusion.

The arrival on the scene of alkaline-powered HID lights (the UK Light Cannon, no doubt only the first of many in the recreational market) raises the issue of color temperature--the whiteness of the light. HID lights are so white, so like sunlight, they almost seem blue and point out how yellow the other lights really are. This fidelity to sunlight is important to the camera but less so to the naked eye, which makes adjustments. (Think about how your eye adjusts to colored sunglasses.) More important, HID lights penetrate water farther because water absorbs the red (and yellow) end of the spectrum more than the blue.

Other features to look for, some of them trade-offs:

• Small size.

• A convenient, reliable switch. (The twist-to-turn-on types have a way of turning themselves on in your gear bag.)

• n Idiot-proof battery replacement.

• Handle choices (pistol or lantern grip).

How I Tested Lights**

In air:** Lights were aimed at a white wall from 10 feet away in a dark room. I measured the diameter of the hot spot. With a sensitive digital light meter, I took readings at the center of the hot spot and at 12 inches and 24 inches from the center.

In water: Lights were also compared for their penetration through about 20 feet of water, a function of intensity and color temperature (whiteness).

A Bright Idea

The diffusion filter supplied with the Underwater Kinetics Light Cannon is a good idea that could be even better. Why not a cup-shaped filter that would snap over the outside of the light, like the diffusion filter for a Nikon strobe? That way, you could switch from flood to spot and back again under water.

Rating System

***** Excellent
**** Very Good
*** Good
** Fair
* Poor

Ikelite RCD Super 8

|| |---| | | | | **
** Rating: ****

This is the light that should be called a cannon. Its reflector focuses nearly all the light coming from the bulb into the tightest possible beam. The result is the brightest and second-smallest hot spot of any light tested, but also second-dimmest outside the hot spot. Not only is the hot spot irregular in shape, it is blotchy, showing shadows of the bulb filament. This, too, is a result of focusing everything on the hot spot--shadows can be erased by diffusing the beam. On the other hand, the Super 8 is one of the most user-friendly lights on the market. Batteries snap into a carrier that holds them in place while the light is reassembled. Polarity markings (+ or -) are clear and unmistakable. The on-off switch is easy to flip with one finger, and has a safety lock. The "Flip-Lock" housing closure draws the two parts together with lever action, so its seal is probably more reliable than the screw type, which might wipe the O-ring out of position. It requires less hand strength, too. The Super 8 comes with both lantern and pistol grips.

Price: $90.
Watts: 15.
Batteries: 8 D-cells.
Bulb: Halogen.
Claimed battery life: 6 hours.
Contact: Ikelite, (317) 923-4523.

Pelican Nemo

|| |---| | | | | Rating: ***

Another cannon, though of smaller caliber. Pelican's new Nemo is focused to the smallest hot spot of the group, only 11 inches in diameter at 10 feet (in air). Outside the hot spot, at 24 inches from the center for example, the Nemo is actually the dimmest. That hot spot is round and smooth, with no shadows to cast false images, and a fuzzy edge. It is exceeded in intensity only by the 8-D-cell lights from Ikelite and Underwater Kinetics, and by the UK Light Cannon. This light is compact. In fact, its bullet-shaped body might fit into some BC pockets. The switch is magnetic and does not penetrate the watertight case, so it can't cause a leak. It is shaped almost like a trigger and is unusually easy to operate. Batteries load into an internal carrier, and their polarity is clearly marked. The carrier locks into the body with a fairly straightforward insert-and-twist arrangement. A spare bulb, though of lower power, is supplied.

Price: $92.
Watts: 13.8.
Batteries: 8 C-cells.
Bulb: Xenon.
Claimed battery life: 3.5 hours.
Contact: Pelican Products, (310) 326-4700.

Pelican Aqua King

|| |---| | | | | Rating: ***

This is what a primary dive light used to be: a monster. The Aqua King is noticeably bigger than the other 8-D-cell lights, both in length and diameter. That larger size allows a couple of interesting features, however, including foam padding around the batteries and springs at both ends. This is supposed to protect the batteries (and the case) from rupture if you drop the light. Also, there is a foot molded to the outside so the light won't roll across the deck when you set it down. Two reflectors are available, giving either a "modified spot" beam or a "laser spot." The modified spot has a very large hot spot (43 inches at 10 feet in air) and good general illumination outside the hot spot. So far, so good. Unfortunately, the hot spot is the blotchiest of any light tested. It looks more like a Rorschach inkblot than a round pool, and it will paint strange images (subconscious or otherwise) on the reef. The on-off-on switch selects either of two filaments in a single bulb. The second filament is a backup. The light's clever handle can be mounted, without using tools, in lantern or pistol position.

Price: $92.
Watts: 14.2.
Batteries: 8 D-cells.
Bulb: Xenon.
Claimed battery life: 10 to 12 hours.
Contact: Pelican Products, (310) 326-4700.

Princeton Tec Shockwave

|| |---| | | | | Rating: ****

The Shockwave is built around 8 C-cells, a popular compromise that makes a more compact light with the trade-off of less burn time. This light has one of the largest, most diffuse hot spots of any (24 inches in diameter at 10 feet in air). Though less than half as bright as the Ikelite's, for example, this hot spot is very smooth and featureless with fuzzy edges and a good deal of peripheral illumination. The beam pattern is a good compromise between a spot and a flood. It actually tested the brightest at 24 inches from the center of the hot spot, exceeded by the UK Light Cannon only when using a diffusing filter. Unfortunately, the light is noticeably more yellow than even the other halogen bulbs, so its penetration in water suffered somewhat. Batteries are fairly easy to load. The 8 batteries stack loosely until the light head is screwed on, which can be a challenge sometimes, but their polarity is clearly marked. The on-off switch is easy to use with one finger, and has a safety lock. With pistol grip only.

Price: $64.95.
Watts: 12.
Batteries: 8 C-cells.
Bulb: Halogen.
Claimed battery life: 4 to 5 hours.
Contact: Princeton Tec, (609) 298-9331.

Underwater Kinetics Light Cannon

|| |---| | | | | Rating: *****

This is the first HID dive light designed for alkaline batteries and intended for the recreational, not the tech, market. HID (for High Intensity Discharge) technology uses a high-voltage arc, not a glowing filament, to produce light. The first difference you notice is that nothing happens when you turn it on. Then a dim glow appears, which builds over about 10 seconds to a brilliant white, almost blue, light. A 10-watt HID is often said to be as bright as a 25-watt halogen. In fact, the 14-watt Ikelite Super 8, with a halogen bulb, was actually brighter in the middle of its hot spot than the Light Cannon. However, the Light Cannon's hot spot was bigger (17 inches vs. 14 inches), and it was much brighter outside the hot spot. So the Light Cannon is clearly putting out more total light than any of the others. Moreover, its hot spot is smooth and featureless without sharp edges. And its very white color penetrates water much better. UK claims 100 percent better penetration of water, and although I was not able to measure that, the difference over the halogen lights was noticeable. A unique feature of the Light Cannon is a pair of diffusion filters included with each light. One or both can be mounted between the reflector and the bezel. One filter turns the Light Cannon from a fairly focused spotlight into a room-filling floodlight. It reduces brightness in the hot spot, of course, but it's well worth it. Two filters made the beam dimmer but no wider to my eye. Underwater Kinetics says that some divers are using that configuration as a video light. Even without filters, the Light Cannon is the brightest of any light tested at 24 inches from the center of the hot spot, and the second-brightest (after the Super 8) at the center. HID lights have other advantages including long bulb life (500 to 1,000 hours), cool running (they can be used out of water where some big dive lights will melt reflectors) and long battery life, considering the light output. The HID bulb is fragile if dropped, however. And there's the price. The Light Cannon's batteries are just a little tricky to stack, and their polarity is not well marked. With a good one-finger switch and pistol grip.

Price: $199.
Watts: 10.
Batteries: 8 C-cells.
Bulb: HID.
Claimed battery life: 4 hours.
Contact: Underwater Kinetics, (800) 852-7483.

Underwater Kinetics Sunlight C8

|| |---| | | | | Rating: ****

The overall size and shape of the C8 is very similar to the Princeton Tec Shockwave, but it's a little longer. Its hot spot is smaller and more concentrated, hence brighter. At 24 inches from the center, the C8 is only half as bright; however, the C8 is a far more focused spot than the Shockwave. Its light is noticeably whiter, too. This suggests that the bulb is driven pretty hard, but there are two of them. Turning the on-off-on switch all the way to the left moves the left bulb to the center of the reflector and activates it. Turning the switch to the right does the same for the righthand bulb. Typically, when lights have two bulbs (or even two filaments in one bulb) the inactive bulb or filament casts a distracting shadow. But the C8 has a reflector with a mottled surface that effectively hides shadows: the center spot is smooth and featureless. The Light Cannon diffusion filter fits the C8 too, and makes it an excellent flood light. Maybe they'll sell you one.

Price: $70.
Watts: 13.2.
Batteries: 8 C-cells.
Bulb: Xenon.
Claimed battery life: 3.5 hours.
Contact: Underwater Kinetics, (800) 852-7483.

Underwater Kinetics Sunlight D8

|| |---| | | | | Rating: ****

The bigger brother to the C8 shares its dual-bulb arrangement. Another common feature is polarity protection: If a battery is inserted the wrong way, the light won't operate. The larger size buys you longer battery life, mostly. The D8 does have a brighter, but smaller hot spot. It's not quite as smooth but very nearly as bright as the HID Light Cannon. The edge of the hot spot fades gradually and at 24 inches from the center, the beam is only average in brightness--about the same as the C8. The light produced is very white compared to other incandescent bulbs, but looks yellow next to the HID and doesn't penetrate as far in the water. With both a lantern grip and a pistol grip supplied.

Price: $85.
Watts: 14.
Batteries: 8 D-cells.
Bulb: Xenon.
Claimed battery life: 7 to 10 hours.
Contact: Underwater Kinetics, (800) 852-7483.

LED Lights: Another Kind of Light

|| |---| | | | | The other major light manufacturer, Tektite, has stopped making an eight-cell light and is instead developing LED lights. Since these "light-emitting diodes" are not really bulbs, they don't burn out and won't break if you drop the light. Tektite's are guaranteed for life. LEDs also give incredible battery life, often in the hundreds of hours. The disadvantage of LEDs is that they are kind of dim--more like a glow than a beam. Work goes on to make them brighter, but, in the meantime, Tektite gets around the problem by ganging them up. There are 14 white LEDs in the Expedition 1400, and 19 in the Expedition 1900. Because it's pretty hard to put a reflector behind 14 or 19 points of light, the pattern of illumination is a wide flood. The result is still not as bright as even the peripheral illumination of the dimmest 8-cell light, but it's close and it's spread over a wide area. I'd call them usable as primary dive lights at close range in clear water, or as backups in more challenging conditions, or as good general flashlights and "gearing up" lights. Contact: Tektite, (609) 581-2116.