Originally posted by bhancox Can anyone explain the AFA auto function mode
Nikon and Canon DSLR's also have an AF-A mode. Like Pentax, Nikon calls it 'AF-A', Canon calls it 'AI Focus AF'. Here's how both explain it:
Canon: AI Focus AF - '
the AF system will automatically choose between One Shot AF [ie AF-S] or AI Servo AF [ie AF-C] based on whether it perceives the subject to be still or in motion'
Nikon: AF-A - '
Auto-servo AF: Camera automatically selects single-servo autofocus [AF-S] if subject is stationary, continuous-servo autofocus [AF-C] if subject is moving'
The Pentax explanation in the K-3 manual is certainly the most cryptic:
Pentax: AF-A: '
Switches automatically between AF-S and AF-C modes according to the subject'.
The common thread between the Pentax, Nikon and Canon explanations is that AF-A lets the camera decide if the subject is still, or in motion. If the subject is still, the camera will dynamically switch to AF-S mode. If the camera thinks the subject is in motion, the camera will dynamically switch to AF-C mode.