Sun 27-Jan-13 08:27 PM | edited Sun 27-Jan-13 08:29 PM by agitater
If you spot meter a very dark area of a generally bright scene, exposure ends up being adjusted for the darker area only. That often blows out the bright areas because in order to properly expose the metered spot the brighter areas end up being lifted as well but beyond the dynamic range of the sensor or film.
Matrix metering usually makes much better use of a sensor's or a film's dynamic range because matrix is designed to find the most appropriate midpoint overall in a frame and adjust exposure on that basis.
Spot metering and area metering definitely have their uses, but it's important to judge the scene to determine whether spot or area metering is needed.