Fixed-focus lens
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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 lens design, and remains fixed. It is usually set to the
The back of an iPhone 3G, showing its small fixed-focus lens
Mid-20th-century medium-format fixed-focus camera
Autofocus
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An autofocus optical system uses a sensor, a control system and a motor to focus on an automatically or manually selected point or area. An electronic rangefinder has a display instead of the motor; t
Fixed-focus lens
…Telephoto lenses are not feasible at a reasonable lens speed. The advantage of this design is that it can be produced very inexpensively, more so than autofocus or manual focus systems. The system is also effectively automatic; the photographer need not worry about the focal point for a given scene. Fixed-focus…
Several green focus points/areas indicating where the autofocus has locked
One selected green focus point using pinpoint autofocus
Active autofocus system via infrared - Canon AF35M (1979)
Early passive autofocus system integrated in the lens with Pentax ME-F (1981)