Have you ever shot with RED? It's a noisy camera, and at 800ISO in low light, it's already noisy (come at me RED fanboys!!!) Crop in to 2K and the noise patterns are even bigger and more noticeable. So, a slower shutter (1/300th instead of 180 degrees) doubled my light intensity and gave the rain drops a longer length...win WIN! You can read in more detail about the shoot HERE :)
The shot below is basically the same lighting setup, but this was shot at 5K 60fps through my Nikkor 50 f1.4 at f2.
For more lighting setups, check out the LIGHTING section at the top of this page :)