I think it depends on the "size" of the photo?If you turn on the optical zoom you can still use digital zoom, may be I am wrong.
有數位變焦啊.......~!怎麼可能會沒有.......那是要看你所設定的片大小啊~!1536X2048(300萬相素)的只能用2倍的光學,1200X1600(200萬目素)就可用二倍的光學+2倍的數位變焦,後面就依此類推~!