My experience with beam quality, with an important technical caveat.
My experience with beam quality, with an important technical caveat. Underwater lighting is one of the clearest examples of how quickly technology can change what a practical configuration looks like.
What matters underwater
In use, I have repeatedly preferred lights built around a strong single emitter and a clean optical system. I am cautious when marketing reduces output to arithmetic such as 'three emitters therefore three times the useful light'.
LED count alone does not determine beam intensity, total output or underwater usefulness; optics, thermal management, current, efficiency and beam angle matter enormously. So my preference is experiential: I look for a convincing beam in the water, not a number of emitters on a product page.
The practical point
The most useful light is not the one with the loudest specification sheet. It is the one that delivers the beam, runtime and ergonomics the dive actually needs.
My preference needed a technical correction
I have often said that I prefer a strong single-LED light because some multi-emitter torches felt less powerful to me even when the headline lumen number looked similar. The correct technical explanation is not that lumens from separate emitters fail to add; they do. What my eye was responding to was more likely beam geometry, optical efficiency and intensity in the central beam.
I keep the preference because I like the compact, concentrated lights I have used—but separating measurable output from subjective “punch” makes the argument stronger, not weaker.
Lumens are only the beginning
A torch can advertise a large lumen number and still be the wrong tool. Beam angle, candela/throw, colour, runtime, switch ergonomics, battery state indication, charging method and size all matter. One correction to a preference I have expressed over the years is worth making clearly: light output from multiple emitters can absolutely add together. What I often prefer about a strong single-emitter light is the beam character and apparent punch, not a claim that three emitters cannot sum to the same total lumens.
My own path went from modest lights, through Mares EOS models, to a compact Tovatec T3500S that became my favourite general torch. I like having enough maximum output for daylight holes, wreck details and signalling, while being able to run it lower at night. I also value direct charging and a battery indicator because those details remove unnecessary battery handling and guesswork.
Primary and backup lights are mission-dependent
For a simple daylight reef dive I may not carry the same lighting package I would take into an overhead environment. For technical or overhead diving, loss of light can become a serious problem and redundancy has to follow training and the plan. The broader discussion in my technical-diving torch article covers why a “bright torch” and a technical lighting system are not automatically the same thing.
Communication should be deliberate and non-intrusive
I dislike turning the underwater environment into a percussion section. Tank bangers and metal pointers can get attention, but I prefer visual signalling where it is appropriate. A light beam can be excellent. I also experimented with a green laser for pointing near—not at—small subjects and getting another diver’s attention. That experience was useful, but the DivePro L6 now requires an important safety caveat because a model recall changed how I would discuss or recommend it today.
My practical light checklist
I care about beam shape at the actual distance I will use it, switch behaviour with gloves, charge state before entry, realistic runtime at the output I expect to use, attachment and backup strategy. A torch can be extremely bright and still be badly suited to the dive if it is awkward to carry, impossible to read or short-lived at the required power.
Explore related topics
This article stands on its own, but these pages go deeper into the parts that connect directly with it:
