• Divevolk SL50 (5000 Lumen)

• Divevolk SL120 (12000 Lumen)

• KELDAN 8XR Ambient (18000 Lumen)

• Sea Frogs SF100 (10000 Lumen)

The Lumen number tells you how much lighting power a specific underwater video light can output at its maximum power level. This is oftentimes considered by divers to be one of the most important figures when deciding for an underwater video light.

This video show you what the actual difference in maximum output power looks like between a 5000 Lumen, a 10000 Lumen, a 12000 Lumen and a 18000 Lumen underwater video light. The test was conducted in a controlled environment (indoor pool) with constant ambient lighting. This is not a scientific test, by any means, but a demonstration of how much of a difference is present between those currently quite popular maximum output levels (=Lumen).

Did he say he used an action cam to record the test ?

Does an action cam auto adjust exposure to make the overall scene look the way it wants ? I don't doubt the Keldan had the most even and powerful output, but if the camera used to record the test is auto adjusting, the real differences btw the lights will be hard to see.

Even if he used a fixed exposure camera to film the test (and I think he did) He demonstrated nothing except (maybe) that the declared Lumen output is more or less correct.

Completely useless.

This is a marketing demo, not a real tech comparison, so nothing interesting. BTW I like Keldan's blueish color. It should give more balanced look.

3 hours ago, KPV said:

BTW I like Keldan's blueish color. It should give more balanced look.

The Keldan used is a actually an ambient-light model, so the colour temperature is shifted in the light itself to emulate what you would get when using an ambient-light filter, but without the loss of power caused by the filter, usually around 1.5 to 3 stops depending on the filter.

Great for mixed lighting, but limiting for macro/night diving applications for instance. And not sure it would work well in the Med's greener water for instance

Meh...
The test would have been more useful if it had measured the amount of light actually falling on the subject, using a fixed camera exposure. He could then have measured the exposure adjustment required to bring the scene to the same level with different lights. The waveform of the pool wall doesn't really tell us much.
Lux or candela measurements would also have been very useful of course, but require equipment.

Other aspects worth testing would be beam angle and edge sharpness, whether the light maintains constant output or dims as it discharge (mean the lumen output is not constant), light runtime at full power for instance.
Super important data, and easily measureable in a pool.

Then there's the question of durability of both the light and the battery pack, which is probably the hardest data point to measure, as it requires actual feedback from actual heavy users. Alex Lindbloom once wrote an article about his 1,000-dive test of his Solas and other brands, which he was using daily while working on a liveaboard. That kind of real-world data is gold.

Edited September 22Sep 22 by bghazzal