Drew, I got into photography to take portraits of unconstrained live fish in my aquariums. I'm not aware of anything that will beat an SLR (film, digital, who cares?) with flash illumination in that application. Studio and lab photography are one thing, shooting mobile subjects is another entirely.
I also shoot small preserved fish, with emphasis on the bones in their fins. For this transmitted light is preferable to reflected and an SEM is pretty useless. This hasn't stopped some nut cases I know who had access to an SEM from trying, though. The shots they published weren't informative.