The Sacramento Zoo is only about an hour's drive from my home. I've spent many happy hours there observing and photographing it's collection of animals. This Caiman was being very active and, in the dim interior light, I chose to use my camera mounted flash to freeze the action.

Nikon D810
Nikkor 70-300mm f4.5-f5.6
Nikon SB-800 Flash
1/100
f11
ISO 1400