Since it is critical to achieve very sharp focus when shooting in High Definition, the HV20 camcorder features Canon's revolutionary Instant AF focusing system. It offers a dramatic improvement in auto focus speed and accuracy (compared to traditional autofocus systems). The Instant AF feature uses an external sensor, in combination with Canon's autofocus system, to help significantly decrease the time it takes to find focus, even in low light conditions. This system achieves focus instantaneously, reducing focus "hunting." The benefits of Instant AF are especially seen in high brightness and night shooting situations. With Instant AF, it's possible to capture fast, accurate focusing, even when following a moving subject.