Cameras, and digital cameras in particular, rely on a lot of basic science and technology to make them work. It's not absolutely necessary that you know everything there is to know about how lenses and exposure meters work, but a basic understanding of them will help you take better pictures. Most of today's cameras have autofocus lenses, either a prime lens with a fixed focal length or a zoom lens, which has a variable focal length, permitting both wide-angle panoramas and telephoto close-ups. They also have automatic exposure meters that measure the available light and adjust the lens aperture/shutter speed combination for the best picture. For some special effects, you may need to override the automatic settings. Keep your camera clean and dry, and avoid scratching the lens. Always keep spare batteries with you when you go out to shoot pictures.