Inside every camera is a light meter that determines the correct exposure for any given scene. Your camera’s meter evaluates what it sees and comes up with the proper exposure based on the light levels of the entire scene. This is usually referred to as matrix metering or pattern metering, and it’s how your camera is setup by default.
Some meters are better than others, but luckily most modern cameras are very good at always giving correct exposure. However, like any technology, the camera’s meter can be fooled, especially in extreme circumstances. A bright light source in the background or on the edge of the photo can trick the camera into thinking that the whole scene is very bright when in fact it is not, leaving you with a dark subject. This is when spot metering comes in handy.
Spot metering tells your camera to focus on one single, small area of the photo to determine exposure, and ignore all of the other light sources in the scene. In the photos above, you can see that in the left image the camera was fooled by the bright lights in the corner and the subject (the branch) was completely underexposed and dark. By switching to spot metering, the camera ignored the lights in the corner as well as the building lights in the background and set the exposure to correctly capture the branch.
Setting Your Camera for Spot Metering
The spot metering symbol is almost always a rectangle with a little dot inside of it. You’re probably using a consumer Nikon, so look for the spot metering option in your menu options as shown below, highlighted in the Metering menu by solid yellow. If you’re using a different brand or a higher end professional camera, you may even have a dedicated button on your camera that cycles through metering modes. Check your camera’s manual or Google it if you’re not sure.
Once you’re done photographing the challenging scene, remember to set your metering mode back to matrix metering for normal photography.
Play around with shooting different subjects in spot metering mode until you get the hang of it. If you find yourself having trouble getting correct exposure on a particular scene with a lot of lights in the background, or with a dark subject, spot metering will probably be the correct metering mode to choose.