Here is a short video i shot yesterday of the 'Little Green Shrimp.' It was shot here in Lembeh using both the Canon 7D and the Canon 5Dmk3 cameras in Nauticam housings.
On the 5Dmk3 i used the Canon MP-E 65mm lens set at 4x, and on the 7D i used the 100mmL with stacked 5x and 10x Subsee Dioptres.
It was, for me, and interesting comparison between the two methods. the MP-E 65 get's built up as an amazing lens but very few take it underwater, and after shooting this i think for the average holiday makers its not worth taking underwater - might as well stack 2 diopters and have more flexibility for almost the same image quality.
Of course this isnt apples to apples as i would need two of the same camera for that, I will try the MP-E on the 7D soon!