Spot Metering – A Beginner’s Guide on How to Use it

Using the spot metering mode on your digital camera can help you make better photos. Spot metering helps you set more precise exposures than other metering modes will. This is because you can narrow the area the camera meter reads from more than with evaluative or center-weighted metering.

Spot metering is a metering mode I use very frequently. I have a function button on the front of my camera programmed to use spot metering. This allows me to switch quickly between Matrix metering and spot metering. I have my camera set to matrix metering by default and will make the switch to spot metering mode when I feel the need to.

In this article, I’ll explain why I like to use the spot metering mode along with matrix metering. Matrix metering is called evaluative metering mode on Canon cameras. This will help you get correctly exposed photography more often than if you are only using the default metering mode on your camera.

All the camera metering modes are helpful. But if you only use partial metering, Matrix metering, or evaluative metering, you will not always get the correct exposure. Using manual mode rather than aperture priority or another automatic exposure mode will also help you be more accurate in getting correct exposures when you take a meter reading.

More About Exposure Metering Modes on Digital Cameras

To make a correct exposure, a camera’s sensor must receive the right amount of light. When the sensor in a camera is exposed to too much light, the photo will be overexposed. If it is exposed to not enough light, the image will be underexposed. Properly controlled exposure metering helps you or your camera set a correct exposure.

A correct exposure is what you decide is right. Photography is subjective. Many photographers aim to have a broad range of tones that contains detail at both ends of the scale. They expect that this is what makes an image properly exposed.

This often depends on the light. Sometimes the light is soft and even. It’s easy to get a correct exposure reading when the light is like this. At other times in your photography experience, you’ll be making images where the light is hard, and there is high contrast. Light meters will not always provide you with the best exposure in these circumstances when they are set to the default mode.

Setting the best metering mode for the light you are working in helps you adjust the aperture and shutter speed for the best exposure settings. In hard light, spot metering is often the best option. When you use spot metering, you can choose the focus point of the meter. The exposure calculation is likely to be more precise and will properly expose your image.

How Metering Modes Work on a Digital Camera

A camera’s metering system is designed to read light reflecting of things as though it is all a particular tone of gray. This is known as eighteen percent gray or middle gray. Camera meters are not intuitive. They are programmed to read light as though it’s reflecting off middle gray no matter what tone your subject is. Sometimes this will cause exposure problems. Using the spot meter in these situations can help you with better camera settings.

When you point your camera at a subject, the metering mode you choose determines how much of the frame the exposure meter reads from. In evaluative or matrix metering modes, light in the whole frame is measured across many different points. The camera will calculate the exposure based on the average of these readings. 

With center-weighted metering,  the exposure meter reads the light from about sixty percent of the frame, weighted in the center.

Spot metering reads the light value from a single point of between one percent and five percent of the entire camera frame. So you can be very precise about the point where the camera will read the light from. This can help set the aperture and shutter speed. Or, if you are using an automatic exposure mode, you can adjust the exposure compensation for more accurate exposure.

Spot metering is the best choice when you don’t want to make an exposure reading from the entire scene or even a large part of the image.