Cwee

Still have it? I'm looking.

Grease is grease: Use it!

Or fill it with clear fingernail polish, then buff lightly with acetone and a Terry cloth. That's an age-old trick that's worked on auto glass for as long as I can remember. Most UW glass is not externally coated, contrary to popular belief (anti-reflective coatings would go on the INSIDE of the dome, if at all) and if you're already annoyed by the scratchyou have nothing to lose in trying. Worst case, you have to strip the entire exterior glass with the acetone if you do have some rare coating there that is noticeably affected. (Test a corner first)

Even with RAW you won't have a red channel below 20' unless you use a filter or artificial light. Make the choice before the dive because a common mistake I see are shooters using a filter with lights and wondering why everything is pink or orange. External light, OR filter, but seldom both. Happy shooting!

I simply cut lengths of pool noodles for mine, and it works well. I used enough that the rig is positive at the surface, fairly neutral around 15', and is negative at 30'+. I know my camera will never run away from me UW but if I drop it off a boat in deep water it's not going anywhere! They're cheap and you'll have to replace them every so often as the foam does permanently crush some after every deep dive, but you can't beat the price.

Very old thread, but do you still have this? I'm currently shooting Subal Type 4 for another body and looking to house my D4. Thanks! -Curtis