Manual focus disables the camera's built-in automatic focus system so you can focus the lens by hand (*). Manual focus is useful for low light, macro or special effects photography. It is very important when the autofocus system is unable to get a good focus lock, e.g. in low light situations. Note that some digital cameras allow you to manually focus only to a few preset distances. Higher-end digital cameras allow focusing using the normal focus ring on the attached lens, just like in conventional photography.