Thanks for sharing your feedback udi62 - Presently I use the D3s underwater and am very pleased with the results, but after buying the D800 for topside photography I've seen some really amazing detail in my topside results when shot in good natural sunlight that i've rarely been able to achieve with the D3s. With that I've started to think about getting the D800 underwater but I just can't find many real feedback reports from people that have spent their own money on their system. In lower light i'm very aware of noise and compared to the D3s which handles less light scenario's very well. I'm also aware of the movement/focus issues that udi62 talks about and topside, i would normally overcome the challenge with a faster shutter speed. What I'm worried about is if i take the D800 underwater to a lower light environment accompanied by the focusing issue that udi62 mentions.....how is the D800 going to cope with say a moving subject like sharks. My gut feeling is...not so well? I've seen John Bantin mention his frustrations with the D800 and obviously udi62 confirms there is a problem...any chance you guys could let me know your thoughts...?