VideoSONY SLT-A33 Autofocus Test

This video is shot with the Sony SLT-A33 using the standard kit lens, the 18-55mm f/3.5-5.6, using the AVCHD codec, at 1920x1080 resolution.

It demonstrates the camera's ability to continuously adjust the focus as the camera moves.  It looks very impressive and smooth.  As the videographer switches from pointing the camera at a subject in the distance to something close the camera quickly pulls the focus.

This is a pretty unique feature of the SLT-A33 because of its translucent mirror technology.  This enables it to use the powerful phase detection focus system of a DSLR for video, which is something that no DSLR can do yet.  Most DSLRs use slower contrast detection focusing when shooting video, this is because the mirror has to be up while shooting video, preventing any light from getting to their phase detection focus system.