[lai37]

點測光, ESP, etc............

[dede]

對準你要測光的點，半按快門，等佢對好焦時也同時好光了，才全按快門

[jasonksh]

from www.dpreview.com

Center-Weighted Average Metering
Probably the most common metering method implemented in nearly every digital camera and the default for those digital cameras which don't offer metering mode selection. This method averages the exposure of the entire frame but gives extra weight to the center.

Spot (Partial) Metering
Spot Metering allows you to meter for the subject directly in the center of the frame (or on some cameras at the selected AF point), this is normally a small circle just 10% the area of the whole frame, the exposure of the rest of the frame is ignored. Useful for brightly backlit or macro shots.

Matrix or Evaluative Metering
This is probably the most complex metering mode, and each manufacturers exact detail on how they implement matrix metering is closely guarded. Sufficient to say that the scene is split up into a matrix of metering zones (between 30 and 200), each of which are evaluated individually, the overall exposure is based on an algorithm specific to that camera. Matrix metering often offers the best exposure possible.