If you’re shooting in strong sunlight you can even take the ISO down to 200, which will reduce grain in the final image without underexposing your photo.
The best ISO setting for wildlife photography is generally mid-range, between 400-800. In most situations this will give you flexibility to shoot a high shutter speed with a wide aperture. If you’re shooting in strong sunlight you can even take the ISO down to 200, which will reduce grain in the final image without underexposing your photo. We typically keep our ISO between 100-500 and ideally no higher than 800.