Lumens for narrow light

[BlueTrin]

I wanted to replace my torch with something a bit better as it starts to randomly turn off by itself and it is not visible in low vis.

I was looking at two torches from Lights for me:

• Tec backup (link)
• Backup XML (link)

The thing that surprised me is that the first torch has only an output of 330 lumens.

Is that really visibly when the water is cloudy ? Is that enough because the angle is smaller so the light is more focused ?

 

[jgttrey]

Pretty standard these days is 600-1000 lumens on a handheld back up (see DGX website, for example). I'd also get an 18650 powered light, which is rechargeable and right-sized for a back up.

That said, it was only an eye-blink ago that 100-200 lumens was considered state of the art for a backup light, so 330, if accurate, is still fine. You're just diving 2015 style. But, more is better (most of the time).

All depends on what you're doing. A night dive in clear water, I find 100 lumens to be more than enough and more than 200 to be too bright. Low viz, the more the better, unless you have tons of silt in which case sometimes dialing it back is easier on the eyes because nothing is going to penetrate very far.

Yes, a narrow beam angle is usually preferable because it penetrates better and is better for signaling. Perfect for me is a hot spot beam with a soft spill around it.

 

[BlueTrin]

I got the Tec model with a narrow light and could try it last weekend. I was amazed at how bright it was in the murky local lake.

The narrow beam was visible and it was easy to signal my buddies.

I was a bit skeptical about how you turn it on: you just rotate the head the opposite direction than to unscrew it but it was fine.

 

[eelnoraa]

I wanted to replace my torch with something a bit better as it starts to randomly turn off by itself and it is not visible in low vis.

I was looking at two torches from Lights for me:

• Tec backup (link)
• Backup XML (link)

The thing that surprised me is that the first torch has only an output of 330 lumens.

Is that really visibly when the water is cloudy ? Is that enough because the angle is smaller so the light is more focused ?

The "tec backup" is using a Cree XPE2 diode. It is designed for high efficiency, not optimize for output. You won't get 330lumen. It is a diode rated for a maximum of 330luman @ 4W consumption. To get to 4W, you probably need to drive 1.5A into the diode. With 3C, this is not sustainable. You 3C can supply ~1A in sustainable fashion, this will get you about 200 lumens if with a R bin diode.

The same applies to Backup XML. It is a XM-L2 diode. With neutral white bin, it is actually very difficult to even archieve 1200 lumen. You need to push 3A into this diode. Again, not possible with 3C cells. You are looking at about 250-300 in reality.

 

[eelnoraa]

Pretty standard these days is 600-1000 lumens on a handheld back up (see DGX website, for example). I'd also get an 18650 powered light, which is rechargeable and right-sized for a back up.

Again, that is max lumen the diode can output. It doesn't mean you can get there. In fact, I have never seen a Cree XML get there regardless of the battery pack size. Most handheld Cree XML are at 250 lumen range in reality.

But I do agree with you, 250 actual Lumen is a lot of light.

 

[jgttrey]

I agree. Except for few mfgs that 'claim' to measure things in some principled, disclosed, way it is just the way they report it.

It has some use comparatively, since what they called a 250 lumen light 4-5 years ago was probably 100. Maybe for different reasons, but the fact remains there is a relatively constant exaggeration factor that I just discount. It's damned bright and way brighter than what they called 200 lumens on the light I bought five years ago. Plenty good for a back up and way more than I need or want on an open water night dive.

 

[JohnnyC]

So, the whole lumen thing and backup lights really starts to muddy the water when people start trying to use backup lights in place of a primary dive light. Backup lights are intended for emergency use. Their design goal is to get you enough light to signal and find your way to safety, whether that's a wreck or a cave or an anchor line or whatever. Their intention is not to light up a cave, or laser beam fight off a shark, or make the whole reef daylight visible so every predator in the water gets an easy meal. Backup lights don't NEED to be lumen powerhouses. They simply need to function, be narrow enough to signal and not blind you with backscatter, and last long enough to get you to safety. This is why massive lumen output isn't necessary, and why many people don't bother getting the newest whiz bang Cree XP9000000 3 million lumen runs off a Tesla power wall for their backup torches.

To this day my preferred backup light is still the Halcyon 3C Scout lights because they're dead simple, just work, I can get batteries literally anywhere, up to and including the dirt road convenience store in the middle of the jungle, and their use is solely limited to finding the line and signaling on the way out.

That being said, since you're not looking for a backup light, there's no need to limit your purchases to those marked "backup" or "tec" or whatever. Get whichever light as the output and runtime that you need to accomplish your dives. There are plenty of manufacturers that offer lights of acceptable quality, output, and runtime.

 

[BlueTrin]

Anyone wants to give me some advice for a cheap canister light that could be used for GUE training ?

 

[michael-fisch]

Buy an old Halcyon 14 lead acid light with 50W halogen slug on the goodman handle, w/o E/O cord. That was the original GUE DIR Light. You can probably get one including the charger now for much less than $100.

Michael

 

[eelnoraa]

It has some use comparatively, since what they called a 250 lumen light 4-5 years ago was probably 100. Maybe for different reasons, but the fact remains there is a relatively constant exaggeration factor that I just discount. It's damned bright and way brighter than what they called 200 lumens on the light I bought five years ago. Plenty good for a back up and way more than I need or want on an open water night dive.

I tent to agree with you mostly except for one minor aspects.

There are manufacturers out there really reported true lumen numbers, such as Halcyon, L&M, UWLD ... Just to name a few. They never claim the max possible. So for apple to apple comparison, it is good to know the actual measurements.