A photographic lens for which the focus is not adjustable is called a fixed-focus lens or sometimes focus-free. The focus is set at the time of manufacture, and remains fixed. It is usually set to the hyperfocal distance, so that the depth of field ranges all the way down from half that distance to infinity, which is acceptable for most cameras used for capturing images of humans or objects larger than a meter.
Fixed focus can be a less expensive alternative to autofocus, which requires electronics, moving parts, and power. Since fixed-focus lenses require no input from the operator, they are suitable for use in cameras designed to be inexpensive, or to operate without electrical power as in disposable cameras, or in low-end 35 mm film point and shoot cameras, or in cameras featuring simple operation. These are usually wide-angle lenses with fixed aperture, and cameras with these lenses generally use a viewfinder for composition.
Especially suitable are fixed-focus lenses for low resolution CCD cameras as found in webcams, surveillance cameras and camera phones, because the low resolution of the image sensor allows a loose focusing on the CCD without noticeable loss of image quality. This makes a bigger circle of confusion and smaller hyperfocal distance.
