Yep, it's guess work trying to take underwater pics with an Optio, since you can't really see the LCD screen. I just try to make the camera angle level with the fish and position the camera anywhere from 10" up to 24" away from the fish. I usually only use two types of modes while taking underwater pics: macro(flower) or underwater (starfish). I do not use the flash, because it often makes the fish really bright and the backround really dark. It's a digital, so don't hesitate to take multiple shots.