Below is a shot of Pablo Vinaras (the head guide at Limay River Lodge in Argentina) on the Limay this April. Split shot just means part of an image is taken below and the other part above the water's surface. I use a large AquaTech dome (PD-85) on my housing with a 14-24 lens to get the wide, split shot look.
Pablo Vinaras. Limay River, Argentina.