A while ago (2020) I was figuring out how to cheaply upgrade the UW video light for the Go Pro.  Maybe it will come in handy for someone nowadays. The goal was to equip both video lights with a dome diffuser. But what material to use? How about a diffuser from a led bulb light. Diffusers have the right optical properties and at the same time can be bought in different sizes. The attachment to the video light can be solved by 3d printing or a quick and dirty variant of attachment using heat shrink plastic (e.g. a suitable part of a pet bottle neck). The important thing to remember is to have a couple of small holes at the top and bottom for water exchange.

Nice

Question did you make a test under water ? Are you happy with the results ?

15 hours ago, CaolIla said:

Nice

Question did you make a test under water ? Are you happy with the results ?

Yes, I was very happy to use them. It's not Keldan quality of course. Cheap Chinese video lights back then had very wide angles, but the problem was if the light cones met in the middle, there were sharp transitions (either shadows or over-lighting if the cones didn't meet or did meet). This all disappeared with dome diffuser. Similarly, when using, say, a GoPro with an Inon UFL-G140 and crawling through a narrow underwater tunnel, the light without the dome diffuser is so hard and unpleasant on the walls. Even most of my buddies looking at the result have started using the same design. I no longer have these lights and switched my interest mainly to photography and gave them to my friend.  But I keep meeting buddies who have been inspired by this design and made their own inexpensive versions. Of course this solution is not even close to Keldan quality, but it's a simple cheap gadget that can help significantly in some cases of very cheap Chinese lights.