From along the Rupununi River, Guyana. Takes largish fish, crabs, frogs, and insects; occasionally small mammals and even scavenges. Fairly common. f/5.6, iso 320, 1/5000. (I obviously could have lowered my iso even further here but it's hard to keep up with things while floating down the river ;), I kept my aperture set at f/5.6 and first try to get the exposure compensation right, then I work on the iso to try and get a shutter speed of 1/400 -1/600 which I seem to need for handholding the f/4 lens. Time permitting of course and if I remember all this ;))