How to Choose A Dive Light
Early underwater lights were fixed electric flood lamps or portable lamps with dry batteries for use by divers in standard diving dress. Siebe Gorman & Company Ltd developed a model of portable lamp with a parabolic lens and attached to the divers corselet via a ball and socket joint allowing the diver to use both hands while working.
A dive light, also called an underwater torch, is a great piece of equipment to own. For night dives, your torch will illuminate dark waters to help you discover the underwater treasures of the evening hours. Dive lights are also useful for day dives, providing critical light when exploring cracks, crevices and providing colour. However, choosing one can be rather challenging with many decision factors behind your first scuba diving light.
LUX vs LUMENS
Lumen is a unit of light measurement otherwise known as luminous flux. We use lumens to compare the total amount of light output from a light emitter. However, lumens isn’t the be-all and end-all. In fact, lumens will only tell you one part of the picture because when it comes to producing a great beam pattern, it doesn’t give you enough information to tell you how the light output is used. A comparable analogy of lumens is an automobile’s total brake horsepower (BHP).
Lux is a unit of light measurement taking area into account. In other words, light intensity. We use lux to measure the amount of light output in a given area, where one lux is equal to one lumen per square meter. Lux is a great measurement for determining what we see as the brightness of a beam. If the light output is concentrated over a smaller area, we see this as very bright. If the light output is spread over a larger area, we see this as very weak. We normally use mirrors, reflectors, and optics to control the path of light and create the desired beam pattern. Lux also determines the magnitude of light intensity traveling over distances. A light that is configured for high lux output will travel farther but will have a smaller footprint of light (e.g. lighthouse spotlight), and a low lux level will be configured to travel shorter distances but have a larger footprint (e.g. decorative down lighting or ambient lighting).
Features to Look for when shopping for dive lights
- O-Ring Seals – Many dive light manufacturers are starting to produce their lights with a minimum dual o-ring seals. The O-ring seals primarily purpose is to prevent leaks. However, it is not necessary true that the more O-Rings there are, the better the seal.
- Material – Injection molded plastic lights are probably one of the cheapest lights in the world. Of recent years, many China and Taiwan companies have entered the underwater diving lights business and started manufacturing lights in Aluminium Alloy. We have seen some rather good quality lights and some really lousy ones. An excellent way to see the quality is to hold it and feel the weight of the diving light (with no batteries in it) and try screwing and unscrewing the battery compartment. Badly made lights will often fail these two test. Delrin is another material that has been used for light manufacturing. These are very durable and expensive lights.
- Type of Switch – Magnetic switches,Toggle switches,External levers,Push-buttons and Screw-on end covers, are some common switch type. Depending on the type of diving and what the underwater light is used for, that will help you decide what sort of switches are best.
- Over-pressure valve – Releases any battery off-gassing — the ultimate dive light safety feature not normally found on torches.
- Nature of Light – You might also want to consider if you would want a light as a Primary light, a backup light or secondary light or are you planning to use it as an Underwater Photography and Video Light.
- Type of Batteries – There are many new lights available in the market that are using proprietary batteries and chargers. Some underwater lights are still running on standard AAA, AA or C size batteries (updated, it is possible to use good rechargeable AA batteries with a C Size adapter). For our secondary lights, we often select lights that allow us to use rechargeable AA batteries to minimize carry too many chargers.
How about burn time?
Burn time – Burn time, is the definition of how long in minutes or hours the torch will produce a useful amount of light. There are many things that affect your burn time such as the batteries you are using, the light mode, the type of LED bulbs that are used etc.