TZ30 - Which aspect ratio to use?
What everyone above me said. Also what you might find interesting to know: the 3:2 ratio comes from the standard 35mm roll of film used in and photo and film analog camera's. When they invented digital cameras they also added the 4:3 ratio because that was the size of TV's and CRT computer monitors. Newer cameras also added the 16:9 because of widescreen monitors and TV's.
There are lots of interesting articles about aspect ratios and the golden rectangle: