My subject is coral and there are several that are extremely small, couple mm in size, that I would like to capture all of the details. The coral is spread throughout a glass aquarium that is 3ft x 3ft x 28inch. There isn't enough space in the tank to try to take shots from within the tank. I won't be able to move the coral around, since they are attached the live rock structures within the tank.
The nice thing about this subject is that, it doesn't move much and I can stop the flow in the tank during shots, so ss can be low. Also, I can adjust the high power lights above the tank to adjust the lighting.