I thought about this, but I was thinking light was so fast that there wasnt anyway the flash would only light the subject and not bounce off the other stuff and get back to the sensor. This still doesnt seem right to me...Couple things. First use during a time of day when it's really cloudy or even in a dimmly lit room. ISO on 100. Then I take it to about f8-f11. Try not to have anything close behind the subject. Use the flash. Shutter about 1/60 or a bit faster. Get the camera somewhat close to the subject, but make sure the flash doesn't get blocked. Take the shot metering on the subject. What happens is the flash only has time to reflect the subject. By the time any other light comes back to the sensor, the shutter is closed.
Most of my stuff is here.
http://www.reefcentral.com/forums/showpost.php?p=18681876&postcount=2
Really I'm still aspiring too!!! I learn more and more as time goes by. You'll see most of the stuff I've picked up so far isn't very expensive, though I've picked up a few good lenses of late. For most of the pics in this thread, the lenses and tube are cheeper ones and everything is set manually, even though the camera's in AP.