Shutter Priority
When auto iris or time delay a is automatic exposure in cameras referred to, wherein the exposure time of the shutter is preselected by hand: The camera adjusts the value of the light metering as a suitable specific F-number automatically. Cameras that have an automatic shutter or time preset are also known as automatic shutter . This mode is marked with S( shutter priority ) or Tv( time value ) on the operating mode dial of most cameras .
The shutter speed is a photographic composition tool. It influences important properties of the image such as motion blur . The automatic shutter is used when the photographer consciously strives for the shortest possible exposure time, for example in sports photography , in order to be able to "freeze" rapid movements of the athletes in the image, or in nature photography when the longest possible exposure time blurs the contours of flowing Water is sought.
Most modern SLR cameras have an automatic shutter control; In the case of compact cameras , higher-quality models usually have this relatively targeted control option for exposure.