How my expectations of a primary light changed over time.
How my expectations of a primary light changed over time. Underwater lighting is one of the clearest examples of how quickly technology can change what a practical configuration looks like.
What matters underwater
I started with a Mares EOS 7ZR, later added a Mares EOS 10ZR and kept smaller lights in backup roles. As my diving developed, I wanted more useful output without adding a large canister system to every dive.
The Tovatec T3500S became the best quality-to-price compromise I had personally found at the time. The important part of the story is not chasing lumen numbers; it is learning what beam, runtime, size and charging behaviour actually matter in the water.
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 lights evolved as batteries and expectations changed
I started with relatively modest output, then added stronger Mares EOS lights while older lights became backups. Eventually the Tovatec T3500S gave me a level of output, compactness and charging convenience that changed what I expected from a general-purpose primary.
The historical Mares lights in my kit are the EOS 7ZR and EOS 10ZR. Older published product information puts them around the 700-lumen and 1000-lumen classes respectively, with the 10RZ using adjustable focus. I treat those numbers as historical context; what matters more is how quickly light technology made the jump to much more output in a package I could still clip neatly to the harness.
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:
