I have a trip coming up and I'm thinking about investing in the underwater case for my canon SD600. I'm happy with the results I get from this tiny yet afordable camera on land (except in low light situations where the high ISO takes over and causes noise). How does it perform underwater? Specifically, how does it perform underwater without a strobe? They cost too much for me right now, but I do want to take some decent pictures while diving. Is the underwater case worth the $240 without a strobe for scuba diving, or will my images suffer too much? Thanks!