I just bought a case for my S200 Elph and was looking for a compatible strobe unit. I've done some preliminary research and it looks like I will need to use a strobe triggered as a slave by the flash on the camera body through a fiber optic cable. So far, the only ones I've see that have that capability are rather expensive like the Sea & Sea YS90. Am I incorrect in the way this works? Are there other less expensive options for a simple point and shoot camera?