Understand Photography
Understanding how a camera’s metering system works is the key to getting a good exposure. DSLRs offer several metering modes. Some modes measure the brightness of the entire scene and some just a small spot.
Matrix / evaluative metering looks at the entire scene and uses sophisticated programming to determine what is in the scene and how best to expose it. The camera makes the right decision most of the time so this is a good every day mode.
Matrix/Evaluative Metering
Spot metering measures a small spot, usually in the center of the frame. In some more advanced cameras the spot is linked to the autofocus and measures at the focus point. When the primary subject is very dark or very bright and takes up only a small portion of the image, spot metering can yield more consistent results. 
Partial metering is similar to spot metering but measures a somewhat larger area. 
Center weighted metering measures the entire scene but applies more importance to the center of the image. 
Regardless of metering mode, the metering system always assumes that what it is measuring is of medium brightness.
- Matrix/Evaluative Metering is a great all around metering choice. Landscapes, portraits and sports all are exposed well using this mode. If a scene has a large, unusually bright or dark area the exposure reading will be incorrect.
- Spot Metering works well when the subject is very bright or very dark compared to the rest of the scene. Use this metering mode on white birds, black cats, and heavily backlit subjects.
- Partial Metering is ideal when you want precision exposure control of skin tones. Often spot metering will sample too small of an area. The somewhat larger area measured by partial metering gives a more accurate exposure reading. Not all cameras have this option. If it is not available use spot metering.
- Center Weighted metering is ideal when the subject is dead center in the frame and of a medium brightness. If this describes your typical picture consider taking our composition course.
