You do very well with available light. Where you seem to have trouble is indoors with a flash. Flashes are horrible lighting. This shot is beautifully done. I like that you have stopped the camera's aperture so that all of the falls is in focus. Bravo, Ells
wished to take a shot a bit closer to have sharper angle of shot, but I've worried about splashes that could hit my lens. It was very warm (+37 C) and me and my friends stands there under waterfall - it was awesome expirience.