As I read various discussion groups, I find answers to things I wonder about.
Q1. Why does the S1iS have an electronic viewfinder (EVF)?
A1. slipe: Because an optical viewfinder can't handle the 10x zoom. Also, I think, because it makes the camera easier to design; an optical viewfinder needs a clear view through the camera body, while the EVF just runs some wires to the camera's sensor.
Q2. Which is better: continuous or single focus mode?
A2. You hold down the shutter button halfway to lock the focus (and exposure), indicated by the rectangle turning green. In continuous focus mode, the S1iS continues to adjust the focus, if objects move before the picture is taken. In single focus mode, the focus is locked until the picture is taken (shutter button is fully depressed).