Cave Divers - Light advice, please

[B.Elster]

I’ve recently purchased Dive Rite’s EX35, flew down to Tulum and found the light much too green. (Reminded me of my local Lake Ontario on a summer day.) The people I dove with used Light Monkey. The EX35 outputs at 5700 Kelvin, whereas LM at 6500, so closer towards the ultraviolet and therefore more blue. Dive Rite’s HP50 outputs 6500 Kelvin. My primary use will be in caves of the Yucatan and some in FL. I do not dive wrecks of the Great Lakes where signaling in poor viz requires a powerful, laser-beam light.

Questions for the group:

• Looking at the photos and/or videos (links below), is my EX35 producing what it should in terms of colour temp? (I always kept it at 100% and am now thinking that I should have stepped it down.)
• On 2 separate days, I noticed a donut hole for about 10 min at the beginning of the second dive. Is this normal?
• I clearly prefer blue over green. Do you think switching the light head from EX35 to HP50 would get me closer to my happy place? Is it a good swap? E.g., HP50 has lower lumens. Does it matter? Are those extra lumens needed/useful in caves of Tulum?
• If you have experience with both, the EX35 and HP50, can you speak to the differences and the conditions/environments where one would be better than the other?
• HP50 has a beam angle of 10 degrees; EX35 has a 6-degree angle. What is that difference like under water? Is 10 degrees good for caves? (I can’t find this info for LM)
• HP50 has a magnetic rotary switch. Does this still work when helmet mounted? (I’m using the Razor helmet mount and like it, so I’d like to keep it.)

If you think of anything else I’m not thinking about but should, please share. I need to decide whether I’m keeping the EX35 or swapping the head out for the HP50. The good folks at Dive Rite, as always, have agreed to help.

Looking forward to your feedback.

https://www.youtube.com/watch?v=qRZ5xRVAPyM

https://www.youtube.com/watch?v=D2kQMImvQAM

 

[Manatee Diver]

Have you tried contacting Dive Rite? Mine isn't green, and fairly closely matches my 5,600K video lights.

Generally in caves a tighter spot with a good lower light level halo is considered to be the best.

 

[Marie13]

I have the EX35 and mine isn’t green either.

 

[B.Elster]

Have you tried contacting Dive Rite? Mine isn't green, and fairly closely matches my 5,600K video lights.

Generally in caves a tighter spot with a good lower light level halo is considered to be the best.

Yes, I've contacted them and they're happy to inspect the light and make things right if the light turns out to be defective.

Since you're using 5600K video lights (similar colour temp to the EX35), I wonder if difference in hue would be noticeable between the two. I only noticed a marked difference when side-by-side with the 6500K LM. We used a high-end Big Blue (don't know the model) on one of our dives. Those burn at 6500K. You can again see the difference b/w its white/blue and my green (upper right) - see attached.

Any idea if a 10-degree beam is a lot different (and better or worse in caves) than a 6-degree beam?

Thanks!

 

[Doby45]

I have dived caves with both the HP50 (my primary) and an EX35 (try dive) and I have not been able to distinguish a difference in the light color. Your eyes must be far more calibrated than mine. If you see a "color" difference it has got to be something in the water.

 

[Manatee Diver]

I only noticed a marked difference when side-by-side with the 6500K LM. We used a high-end Big Blue (don't know the model) on one of our dives. Those burn at 6500K.

Generally in the 5,600K range is preferred for more natural looking colors. 6,500K lights are very blue light. You look at high end video lights and they are typically between 5k and 6k. Also Big Blue has 5,600K lights.

Here is the EX35 in a mixed lighting environment.

White balance is set to 5,500K, Light & Motion Sola Pros on camera, and a Big Blue warm white 15k as a drop light behind me.

 

[jlcnuke]

Regarding the difference between a 10 and 6 degree spot, it is quite significant, especially in higher turbidity/silty/low vis conditions. In fact, it's the primary reason I'm probably replacing my D630 primary with something with a more defined and tighter spot like the EX-35 or a Light Monkey or UWLD light instead.

 

[Alaskan Scuba Dude]

Is this a fear factor prelude, or am I to empathize why most people prefer to leave all the lights on while at home. I’m quite the opposite. Using high output lights in caves covered with tannin, like the Pit near Tulum, may have adverse effects in visibility.



...aka Vocal Underwater Explorer...

 

[B.Elster]

I have dived caves with both the HP50 (my primary) and an EX35 (try dive) and I have not been able to distinguish a difference in the light color. Your eyes must be far more calibrated than mine. If you see a "color" difference it has got to be something in the water.

@Doby45 How did you find the spot angle difference? Was HP50's 10-degree much different than EX35's 6-degree spot, as @jlcnuke says it is?

 

[Doby45]

@Doby45 How did you find the spot angle difference? Was HP50's 10-degree much different than EX35's 6-degree spot, as @jlcnuke says it is?

I personally did not perceive the difference, but I also was not focused on that. (Get the pun?) I will say this you will not go wrong with either of those two lights.