[Tank]

Hi
I used the F810 in the red sea for a week...Nice wide angle feature on it....

Shoot on manual all the time!
If your pointing the camera up towards the sun bring the Aperture to maybe F8
If your pointing to an object like a fish or topology, bring the Aperture to F2.8 or around that....Theres no difinitive setting that will work all the time...Have fun with it and enjoy changing the settings to see different results..
Shutter speed probably safe with 1/125...but pointing to sun bring up to a faster speed...say 1/250
Use the zoom and you can also switch during the dive to wideangle but if i remember right, you dont have the zoom feature then.