DIY Diffusers

[SlvrDragon50]

So my dad bought me a pair of Magicshine MJ-878 for my birthday:
MagicShine MJ-878 2200 Lumen 100 Meter (330 feet) SCUBA Diving Flashlight with Rechargeable Battery & Charger - Amazon.com

Which seem to be awesome for the price for a primary light, but the intention was to get video lights since I already owned primary lights (he didn't know you want a wide angle for video). Since he dropped so much money on them, I would really like to find a way to get them to work for video.

The light only has a 15*, 2200 lumen beam which is incredibly focused for the 170* FOV of the GoPro HD2. I want to add a diffuser, but everyone recommends getting one from a UK Light Cannon which I cannot seem to find anywhere.

Any DIY suggestions? I've come across bubble wrap, pringles cans, light diffuser material from Home Depot.

 

[flareside]

Getting from a 15° source to the roughly 100° field (each from 2 lights) that a GoPro needs is not likely possible with a diffuser, at least to where there would be any light quality left anyway. Diffusers are too ineffecient and block too much light.

Best suggestion would be some form of optical correction. I did a quick experiment with a pocket fresnel lens that showed some promise. (ex: 6 PCS CREDIT CARD 3X MAGNIFIER MAGNIFYING FRESNEL LENS | eBay) Two layers showed even more promise but that was all I had to work with. If you can find a cheap source you might try stacking up 4 or 5 of them. Water however will largely negate any effect they have so you will need to find a way to seal around the outer edge of all the layers to maintain the air in the grooves.

You will find that the more you expand the angle, the quicker the light level drops as it is being distributed over a greater area so you will have to find the happy medium between light level and how much of the frame to fill.

Again, this is just a suggestion. Beyond this point, you're on your own.

(And be sure you don't overheat your lights)

 

[SlvrDragon50]

That's what I figured. I was hoping that with 2200 lumens that I would be able to diffuse it quite a bit and still have maybe 600-800 lumens to work with. Would you happen to know if those fresnel lenses would be able to tolerate the heat generated by the lights?

 

[flareside]

I really can't say if they will melt as I don't have any lights that strong to get a feel for how hot they get. I certainly wouldn't try installing them inside the light housing. But by mounting them out front, the water "should" keep them cool enough.

To mount the lenses, consider taking a cheap UV filter with a full depth frame that matches the front diameter of your flashlight, pulling the locking ring, and then building up layers with a small bead of liquid silicone glue around the perimeter of each layer and then finish off by putting the locking ring back in place (if possible). For good measure, it would also be a good idea to pull the glass and reseat it with a bead of the glue. And if you haven't worked with the liquid silicone glue before, it is extremely flowable and hard to control so you will want to put the bead in place with a plastic tipped syringe. The nice part about the flowability is that it will easily fill the threads inside the frame and seals everything up really well. But use it sparingly, just enough to fill the perimeter voids. You will not be creating a true "bead" like you do with silicone caulk.

Give it at least a week to cure in a warm humid environment. Mount the assembly with waterproof tape around the barrel. And while I can't guarantee the light won't melt the fresnel lenses (and I have no reason to believe it will), at least if it does, it will melt them to the UV glass and not damage the flashlight. I hope this helps.

 

[fer_abella]

The best light would be obtained if you take out the original flashlight "parabola" and put somehow the leds near the glass. this will bring you very nice light.
If not, you can always take it just out and try the light from actual led positions, light will be a lot less focused.

 

[3D diver]

I've been tinkering with diffusers:

http://www.scubaboard.com/forums/gopro-video/425784-my-gopro-3d-setup.html

With 2200 lumens you'll likely find the simple external white diffuser adequate.

 

[SlvrDragon50]

That's one of the methods I saw 3D diver. I don't have the lights on me right now, I think I will get them next week.

I'll have to try that out.