With HD, focus is more critical than ever. It demands Instant AF: the next generation of auto focus, designed with HD resolution in mind. Because HD resolution is higher, focusing time is longer -- it's harder to find perfect focus. Canon's Instant AF combines an external AF sensor with Canon's legendary auto focus system for fast and accurate focus. Together, the two sensors reduce focusing time -- even in low-light, low contrast, or high brightness situations -- and improve focusing performance on difficult subjects.
The XH A1 gives you a choice of 3 AF modes for different shooting applications:
Normal AF changes focus at a speed that appears natural and doesn't distract the viewer
Instant AF changes focus as rapidly as possible and is designed for applications in which quick focus is more important than other considerations -- for example, in new gathering or documentary work