I photographed this red eye tree frog in Costa Rica during a rain shower. Notice how the 1/200th of a second shutter speed was fast enough to render the frog sharply yet it allowed the falling drops of water to leave streaks. You can vary the length of the streaks by adjusting the shutter. I used a 100-400mm Canon zoom so I could fill a significant portion of the frame with the frog without scaring it away. The camera-subject distance was about 6 feet. My lens aperture was f/9, and the ISO was 2000. Some photographers use flash when shooting in a tropical forest because of the reduce light. I avoid flash if possible because the resulting pictures look a lot more natural.