This pictures have been taken in the Mediterranean Sea... in the same conditions as it was at the same time !

Sigma 15mm - f11@1/250ème sec - depth : 7m / 20feet

Sigma 15mm - f8@1/250ème sec - depth : 15m / 50feet

S5

Sigma 15mm - f8@1/250ème sec - depth : 20m / 65feet

S5

Conclusion

The UW shooting conditions will give us a nice Sunball or not… but not the camera’s brand! The S5 Pro won’t improve our underwater pictures except, maybe, in producing people natural skin colors. Above water, for sure, it will allow capturing high-contrasted scenes.

While it sharpness is not as good as the D200, the S5 pro brings colorful pictures – somebody used to it could make much better pictures as those shown here! It biggest disadvantage for me is that there is no tool like Nikon Capture NX at this time. Meanwhile, the S5 could be a good option if you want a backup camera…

Fuji is for a short time now interested in improving picture quality rather then number of pixels – I think we’ll have to wait a long time before manufacturers would take care about underwater photographer’s problems as we are no a lot!
I would even say that our "problems" will (perhaps) been solved by chance, without taking care of any uw needs.

Thanks to Max Briatte and Laurent Kbaier for their help to do that back to back assessment;)

Fuji S5 Pro - f8@1/100ème