I get a lot of questions about when to switch to Spot metering (a metering mode that measures just one small area of the photo). I can tell you that 99% of the time, I leave my camera set to Matrix (or Evaluative on a Canon) metering (the standard metering mode that does an amazing job of getting you good exposures without having to break a sweat). However, there are times (few though they are) where I need to switch to Spot metering and those are where there’s something in the image that I’m worried about being properly exposed. Now, do I worry about something being properly exposed when it’s well-lit? Nope. Usually, it’s when something that’s really important is in bad light—like a shadow area of my photo. So, in short, when there’s something in the photo whose exposure needs to be right on the money, I switch to Spot metering just for that shot, and then I switch back to Matrix (or Evaluative), which works wonderfully in 99 out of 100 situations.