New diver beam angle questions

[SCRedWolf]

Hi, I'm a new recreational diver with a couple of questions related to beam angle. I'm looking to buy my first light or two. They'll be used for dark areas on daylight dives and possibly some night dives, in New England as well as some warmer/clearer parts of the world. No video or photography, just want to see what's down there.

• In New England water I know backscatter becomes an issue. But what beam angles work well in silty water? I'm sure 60*+ becomes a mess, but what about 30-40*? 15-20*? Is it necessary or advisable to go all the way down to 8*?
• Do the focusable lights like the ones from Bigblue and Tovatec work well?
• Do you consider beam angle when picking primary vs. backup? I.e, a wider light for primary and a narrower one for secondary?
• Should I even worry about this, or just buy a decent looking light?

I've got no real experience and it seems like there are tons of choices, so any advice appreciated!

I think an 'average' dive light fills the needs of generic use. Personally I use a Princeton Tec League for my night dives and some of my daylight dives that I know I want to see in some shadowy areas. They're not expensive and actually work pretty well. I've had them for two years and they've been on almost 50 dives. I like the tight focus of the center of the beam but it has about a 40-degree spillover which lets you see stuff just off to the side. The manufacturer says it's a medium beam. For $30 it's cheap enough to see if you like it and if not demote it to keeping in your car. For what it's worth waterproof lights make awesome emergency lights to keep in your vehicles. Anyhow, that's my 2-cents.

 

[TheRealScubaSteve]

Get a DRIS 1k or the shorty version if you want to stow it. I think it's a 10 or 11 degree angle and it works great for NE water. It does throw some light with a halo, but when it's murky it won't get through except for the hot spot.

 

[kr2y5]

Hi, I'm a new recreational diver with a couple of questions related to beam angle. I'm looking to buy my first light or two. They'll be used for dark areas on daylight dives and possibly some night dives, in New England as well as some warmer/clearer parts of the world. No video or photography, just want to see what's down there.

• In New England water I know backscatter becomes an issue. But what beam angles work well in silty water? I'm sure 60*+ becomes a mess, but what about 30-40*? 15-20*? Is it necessary or advisable to go all the way down to 8*?
• Do the focusable lights like the ones from Bigblue and Tovatec work well?
• Do you consider beam angle when picking primary vs. backup? I.e, a wider light for primary and a narrower one for secondary?
• Should I even worry about this, or just buy a decent looking light?

I've got no real experience and it seems like there are tons of choices, so any advice appreciated!

For illumination, in open water, you do not need (or want) much power output, pretty much anything will work. For signaling, IMO you really do need a focused beam, or else the light won't penetrate far enough without creating a lot of backscatter. The lights that are designed to have a fixed 6-8 degree beam usually spill some amount of light around the host spot, which is just enough to illuminate the surrounding area. I have a LM light with 6-degree spot, and some light spill around it, and I'm happy with it. One of my cheap backups has a focusable beam that can be made even tighter, but it concentrates all the power in the hot spot, which is really suboptimal during night dives, for you don't actually see much outside the spot it illuminates, and if you're using such a light as a primary, sometimes it's hard to see where you're going.

 

[OrcaTorch]

A wider beam angle with no hot spot is often used in dive video light . If you just dive in silty conditions without photography, highly recommended this one:
OrcaTorch D810 dive light-- 950 lumens with 8 degree focus beam angle and 70 degree flood beam angle

 

[kr2y5]

Based on the above, for our PNW conditions, I would personally pick the "competing product". YMMV.