My GoPro 3D setup

[jmneill]

Hey 3D, can you post a link to the white diffuser you are using. It looks like too much to me from your pics, but I would like to give it a shot anyhow. Guess I won't have it in time for the weekend, but maybe I can squeeze in a mid-week dive and post back if you haven't made it to the water yet. What are your thoughts at present in reguards to internal diffuser (with or without reflector) vs external white diffuser?

 

[3D diver]

I started with three sample diffuser blanks from Tap Plastic---see my post #11. I assume similar material is available at large hardware store chains like Home Depot, Lowes, etc.

Edmund Optic has fancier sand blasted glass diffusers that work on the same principle and may pass more light:

Commercial Quality Sandblasted Glass | Edmund Optics

Ground Glass Diffusers | Edmund Optics

Opal Diffusing Glass | Edmund Optics

What are your thoughts at present in reguards to internal diffuser (with or without reflector) vs external white diffuser?

Right now I'm leaning toward the white diffuser. You lose intensity but the beam spread is amazing. I took a walk around my back yard last night and my entire field of view was lit. My only hesitation is whether it's bright enough for the GoPro. I think the beam spread would be ideal for your cavern dives.

Moving the diffuser inside the light preserved its beam width, but it still has a hot spot. A better diffuser like the Edmund Optic double concave lense might improve it, but I want to test what I have already before going down that path.

Uncoated Double-Concave (DCV) Lenses | Edmund Optics

My plan is to use an external white diffuser on my next dive---either the ones I have or a couple from Edmund---& see how it goes.

---------- Post Merged at 10:05 AM ---------- Previous Post was at 09:53 AM ----------

This is all I could find on the Tap Plastics web site about the diffusers I've been tinkering with:

http://www.tapplastics.com/product_info/plastics_information/light_panels

I believe my external white diffuser is their "smooth Opal acrylic".

Here's something similar from the Lowes web site:

http://www.lowes.com/ProductDisplay...gId=10051&cmRelshp=req&rel=nofollow&cId=PDIO1

I'd want to see it before buying...

 

[jmneill]

Thanks for all the links 3D. I had looked at Tap's site but couldn't identify what you were using. Got the credit card out to go for the Edmund Scientific Opal diffusing glass but found that they don't have it in close enough to the size I need. I don't think the sandblasted or ground glass they offer will provide enough diffusion. I found the chart below for sanblasted glass in various grits indicated by color, and assume sandblasted vs ground are going to lend similar results.

That said, I think a trip to Lowes is in order to check out what they have. Or still, I may bite the bullet and resize a couple of these I-torch diffusers.

 

[3D diver]

If the I-torch diffusers are close to your current light diameter you might consider using duct tape for a dive or two.

I'm a bit dismayed by the transmittance chart, I expected it to be a bit more uniform. The human eye compensates for a lot of exposure difference so it's hard to assess the coverage just looking.

Really, any sheet of white plastic may do, I even considered using a white trash bag for tinkering purposes. With a scattering style diffuser you're going to lose an f stop or three---what plastic/glass to use depends on how much you're willing to lose.

 

[Lizard Leg]

I took the reflector out of mine, and it really seems that (expecially with two of them) that this would be fine for GoPro or still pictures close range - say 2-6'. I mainly dive in clear water - 20' vis is a bad day, so maybe my expectations are a little lower.

 

[jmneill]

Really, any sheet of white plastic may do, I even considered using a white trash bag for tinkering purposes. With a scattering style diffuser you're going to lose an f stop or three---what plastic/glass to use depends on how much you're willing to lose.

Yea, I even saw someone reccommending a cutout from a pringles lid on another board.

 

[flareside]

Plastic from milk cartons may also be viable.

 

[Marty Cerven]

I have tried a opaque white plastic bag on my TUSA 300 lights, this did a good job on land tests but underwater the loss of light made the lights fairly useless at that lumen level. I did use them as close up fill lights like this with my Sola's aimed a bit further away and it worked ok but didn't make enough of a noticeable difference to just using the 2 Sola 500's on their own.

 

[3D diver]

Yeah...only 40% transmission...but the spread is impressive.

Been reading up and shopping today for Holographic diffusers---85% transmission!!! Expensive though, over $100 from Edmund. Traded emails with an outfit offering a Holographic diffusion sheet, 10" by 10", with a 60 degree angle for $35.

 

[jmneill]

Yeah...only 40% transmission...but the spread is impressive.

Been reading up and shopping today for Holographic diffusers---85% transmission!!! Expensive though, over $100 from Edmund. Traded emails with an outfit offering a Holographic diffusion sheet, 10" by 10", with a 60 degree angle for $35.

I'll be happy to lower the cost of that sheet even further by purchasing your leftovers! All I need is 1.5" X 3"