Instruct: Classify Amazon reviews into positive or negative sentiment
Query: dark spot

I purchased Canon Powershot S2 IS 3 years ago.This camera was a great product until 2 years ago I noticed there was always a dark spot (>5% of the whole field) located at the center of the view of movies that I took outdoors, especially with sunshine. The spot just gradually shown up after several seconds when the lens pointed to bright background.Now that dark spot becomes darker and bigger and even appears when I take pictures and movies indoors.I think certain areas of the digital film in the camera was damaged and desensitized.I'm unwilling to spend at least half of the price of the whole camera to replace the digital film.