The couple on the Alaska trip with the 500 and 600mm lenses, called the 600mm "JR" ; they actually named the lens. Both lenses had their own special backpacks, and industrial tripods.
Nice action shots on the pelicans.
Our Alaska trip was at the end of the film era; we took 3600 frames of slides. With bracketing, some shots had three pictures. If focus and exposure were not perfect, all of them went. We threw away 100's and 100's of shots. We had done plenty of photo work before, but catching shots of humpbacks in full or partial breach was challenging. But, we got some great shots of humpbacks breaching and bubble-feeding, Orca's, Grizzly bear at Pack Creek, etc.