S90 lens problem
Check your S90 lens. You'll find that the lens is not flat. Instead, it looks like a donuts floating on water.
Try to take a photo for a blue sky...you 'll see the donuts in your photo...the effect if more significant when the picture is viewed in the S90 screen.
You may check my photos here.
There are 2 photos here. The first one if the original and the second one is a tuned one that I have boosted the saturation and contrast so that you can see the donuts more easily.
I called the customer service already and they agree that the donuts appeared in my photo and they have no idea why it happen. They said they will inform Canon Japan and see if there is any solution.
Did other S90 users has the similar issue?
Maybe the advertisement is correct. S90 is good for night shoot...only...