Beam Angles

[Packhorse]

One of the most important yet sometimes overlooked aspects of a good light is beam angle (IMHO).

I like a nice tight beam with little or no side spill so it reduces back scatter and penetrates deep through the often less than optimal viz waters.

Others may prefer a wider angle when doing 20 meter + viz night dives.

What are your prefferances and why?

If you have a adjustable focus light what setting do you normally use and how often do you adjust it? If you could only have one setting what would it be.

 

[Greendiver]

I can tell you what I don't like, wide flood like beams without the power to sufficiently light my target. I know what I want to look at/for and without enough power to light everything, I would prefer to focus the light on my target. Of course I have only used small underpowered lamps.
Now if I was able to enjoy the crystal clear waters that some of you have, this may be another matter altogether.

Is it possible to have 2 sets of LEDS in the same head to allow you to change the output from narrow to wide?

 

[Packhorse]

Yes it is but at a cost of space. Each would have to have its own optics or reflector. I have thought of building such a light but in the end went for 4 LEDs with a tight focus.

 

[klemheist]

Hi Greendiver,

Yes, it is possible to have different focusses in the same LED head, providing you are using more than one LED.

For example, a Terralux TLE-300M head uses 3 Cree XR-E's. They all come with tight 8degree lenses. If you want to replace one or more (or all) of the lenses with wider angles then it's as simple as sourcing the lenses and unscrewing the front facia.

The Terralux fits into a Maglite head, commonly used in DIY underwater torches. It runs at 12watts and gives 500lumens of white light (roughly equivalent to a 10W HID).

Here's a couple of pictures of what I'm talking about.

That said, personally, my advice would be always to go tighter beams given underwater particulate will always scatter the light for you.

Mac

 

[mbsub]

Hi Greendiver,

maybe you speek about this LED-head?
mb-sub.com: LED-head TWINLED....NEW!

Its a LED-head with 2 x OSTAR LEDs and each with a different reflector. From this system you can read a big test in some days here in this forum.

Michael

 

[Greendiver]

It is hard to imagine where a wide beam would be that much better than a tightly focused beam unless the conditions are crystal clear. Such as a swimming pool!

To be starting my first DIY lamp it will have 3 or 4 LEDS but they will all be focused the same simply because I'll wait for the more advanced stuff later. Mbsub, that stuff looks great! However, not much of a DIY project.

 

[klemheist]

Mbsub,

Those twin LED's look the business but you might like to pay off the Goodman style handle as it is dated technology.

If you want true hands-free lighting why not try a wetsuit material type light holder. Easy on and off and all fingers free at all times.

See attached pictures of a couple of wrist rigs

Happy diving

Mac

 

[mbsub]

Hi Mac,

the answer is simple!
Tec-diver dont want this kind of holder.

Michael

 

[mikerault]

My Can light head just moves the LED/reflector back into the hood to focus the beam tighter, why would you need 2 sets of lights? Just add a focus capability to the existing head.

 

[mbsub]

@ Mikerault

If you change the focus from spot to a wider beam you lost brightness , because the sended light will be dispensed to a bigger area. Also you get the donut-effect.
We use the 2 LEDs to add the lightpower from the second LED with medium-reflector to balance the lost of brightness.
BTW the TWINLED head exist also in a version with 2 spot reflectors.

Michael