1. A method for adjusting weighting values in light metering, comprising: dividing an input image into multiple metering zones, the input image including a plurality of pixel data and the metering zones corresponding to a plurality of exposure weighting values; determining whether color of each pixel datum of the input image is skin color; calculating an amount of the pixel data determined as the skin color for each metering zone; and adjusting the corresponding exposure weighting values of the metering zones according to the calculated results.