What zoom levels are available on the PowerShot ZOOM and what magnifications do they correspond to?

Each press of the zoom button cycles between three zoom levels: approximately 100 mm (optical), approximately 400 mm (optical), and approximately 800 mm (digital). These correspond to telephoto magnifications of approximately 1.2×, 4.8×, and 9.6× respectively for both still photos and movies. Note that image quality is lower at the 800 mm digital zoom level. (Page 113)