I recently posted about pulsing an LED for 1uS on at 10Hz. Now I'm trying to pick an LED for this project but I'm wondering how to understand the LED rise time and weigh different LED characteristics such as radiant intensity. If there's a 1uS pulse to turn the LED on, and the LED has a rise time of 5ns, is that more then fast enough? How slow of an LED rise time could I get away with or how can I determine that? I assume the higher the radiant intensity and the smaller the angle of half intenisty the more narrow and farther the distance the LED will go?