S45/50: Difference in Light Metering Modes

[hwaitah]

Hi, I'm a new owner (1 month) of the S45 and I love it. Still learning the features everyday. The light metering modes in the manual is not explained well enough. You basically have 4 modes ie.


1) Evaluative light metering
2) Center-weighted averaging
3) Spot AE Point - Center
4) Spot AE Point - AF Point


Which mode(s) do you normally use and when? What's the difference between (2) and (3)?

Thanks in advance.

Lee