Uh oh, my Canon S230 is broken...
..Have had for 6 months, everything has been ok. Today, I turned on camera, and the optical zoom only worked via the LCD screen-on the viewfinder, there was no apparent change in zoom. So, I had 2 different views!. Since I was shooting in macro mode, the zoom in the viewfinder was essential, so I turned the camera off and looked in the manual. That didn't help.
Then I turned the camera on and off a few times, and I got a blank screen with the following notation: "E18"
I ain't completely stupid, I figure that means Error # 18.
Well, I will call Canon on Monday-thank goodness it has a 1 year warranty and I actually found my receipt.