Olympus D 550 Zoom

[Fishmove]

I have an interest to start doing some underwater photography and was wondering if anyone has experience with the Olympus D 550 Zoom. I have looked and looked and have only one housing that would cost me about $600, ridiculous! I read that I might be able to use a EWA Marine soft housing for the camera even though it's meant for a different camera. Even if I did decide to go this route and use the soft (bag) housing how would I be able to hook up a strobe to it. I know that they make strobes that can work independently from the camera via remote sensor, yet that option is very pricey as well. My last question is at what point do you need a stobe, when the camera's flash is no longer capable of providing good quality pictures.

thanks for any and all help!!