In this render, the camera is only 20 feet below. Observe how the scattered light is arranged differently, because of the camera position.

Impressive results. This makes the render that holds the eye,, captivates.

I wonder about the reflection of the subs under the surface of water. If you get this much "caustic" effect below, shouldn't the reflection be almost destroyed? The reflection there truly is a moving target...

This is "groundbreaking" for poser. I hope you post some rendertimes.