autofocus
Sign in to saveAn autofocus (AF) 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; the adjustment of the optical system has to be done manually until indication. Autofocus methods are distinguished as active, passive or hybrid types.
Article
17 sectionsContents
- History
- Active
- Passive
- Phase detection
- Contrast detection
- {{anchor|Illuminator}}Assist lamp
- Flash-based
- Laser-based
- Hybrid autofocus
- Comparison of active and passive systems
- Trap focus
- AI Servo
- Focus motors
- Notes
- See also
- References
- External links
An autofocus (AF) 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; the adjustment of the optical system has to be done manually until indication. Autofocus methods are distinguished as active, passive or hybrid types.
Autofocus systems rely on one or more sensors to determine correct focus. Some AF systems rely on a single sensor, while others use an array of sensors. Most modern SLR cameras use through-the-lens optical sensors, with a separate sensor array providing light metering, although the latter can be programmed to prioritize its metering to the same area as one or more of the AF sensors.