Set the camera to its widest aperture and set the shutter speed.
Let’s start with Manual Mode. This is M on the camera’s mode dial. Set the camera to its widest aperture and set the shutter speed. The general shutter speed rule is 1/lens focal length. So, if you are shooting with a 300mm telephoto lens, the lowest handheld shutter speed is 1/300 sec. I suggest you double that to 1/600sec; photographing wildlife calls for a faster shutter speed.