I cannot explain your conclusion, that 4X and 12X produce equal results.
Here is a link of sample photos taken with the S2 IS:
The shots of the boats are taken at 36mm, 115mm, 227mm, and 432mm (focal lengths).
I don't see how a 4X camera with a focal length of 35mm to 140mm will equal that.
I was recently at a camera shop where I was comparing both the Canon A2IS and the Canon A620.Both cameras impressed me but while zooming in on a subject I found the A620 to be just as close as the A2IS.Is that possible given that one has a 4x's digital zoom and the other a 12x's digital zoom.The distance was only about 80 feet,but both cameras brought the image in just as close and really I thought the A620 was a bit clearer.Can someone help me with a reason why this is posssible or is it just that the 12x's zoom needs to be further away from a subject in order to see the full potential of the A2IS zoom.I am thinking about the A2IS but now have doubts and think the difference in mega pixels between these two cameras makes the A620 an even better camera.Any comments to help me make a decision.Thanks