A good example case would be the first one on this website:
planet neil - tangents 01 - exposure comp.
If you focus on the two people AND use matrix metering AND have the AF-AE link off, the picture would be overexposed because the camera would try to bring the shadows up (which is in the center of the scene). If the AF-AE link is on, it would be less overexposed since the camera will put more weight on the focused area when metering.
The camera would still meter from the whole scene in both cases, but the linked option would make it less underexposed since there is more weight put on the area you choose to focus on. IMO in this kind of case it would be better to use spot metering anyway... but I haven't run into these kind of situations myself. Personally I feel it's kind of cumbersome to play with the menu so I leave the link off and just play with the exposure compensation. I might give the AF-AE link a try and see if it makes shooting any easier for my subjects. Please CMIIW
I'm a guy and I read the manuals, btw ;b
Last edited by Andi Lo; 08-10-2008 at 10:16 PM.