All digital SLR cameras have a feature called “Metering Mode,” “Exposure Metering,” or just “Metering.” Understanding how camera metering functions and what each of these modes does helps you control the exposure and take better photos in difficult lighting conditions.
So what are camera metering modes
All cameras have their own built-in light meter and when you point your camera at a scene, the meter calculates the amount of light reflected by the subject in order to expose it properly. So basically, each metering mode will tell the camera how you want it to approach each particular shot.
The most important metering modes are:
– Matrix / Evaluative metering
– Center-weighted metering
– Spot / Partial metering
In most cases, the camera’s default metering mode (called matrix metering) provides pretty good results. However, there are some scenes (usually when you have very bright or very dark areas in the frame) where the camera’s default metering fails to give you the best exposure.
This is when the other metering modes come in very handy. These metering modes are computer programs that give more emphasis to certain areas of your shot and determine the proper exposure for your subject.
Let’s explore the three metering modes and see which one is best for you:
1. Matrix / evaluative mode
This is the “default” metering mode on most cameras and the metering is determined by how light is spread throughout the image. The camera uses the whole scene within the camera’s viewfinder to give you the most accurate metering. This is your best option when you’re not sure which metering mode your subject will require.
Here is how auto exposure works: the light meter splits the frame up into smaller parts and then assesses each area for shadow/highlight details. Then it takes the average for each of these areas and calculates the overall exposure resulted from that number. In matrix mode the camera attempts to assess everything in the frame and take the best guess by averaging all the elements to determine how to correctly expose your subject.
One of the main elements (besides distance, saturation, highlights) that influence matrix metering accuracy is the focal point. After light reading all these areas, the meter determines your focal point and identifies that zone as being the most important of all the other ones.
This metering mode works well for general projects, especially when you’re using multi-point autofocus, where you have multiple autofocus points into the foreground with different light levels. Matrix mode will then average the light and dark areas in the foreground and create a properly exposed image, like in the example below:
Matrix metering also works well for scenes that are evenly lit when you must get an accurate light reading on the whole scene and set the exposure very quickly. It can also be a good choice for scenes with a high contrast between light and shadow.
2. Center-weighted mode
Many people like to use center-weighted metering because it’s reliable and know just what to expect. If you’re focusing on the middle of the image, that’s where you’ll get the most consistent light levels.
Some cameras even let you to change the size of the metering circle, which in fact is one of the best types of metering, since most subjects are centered in the shot and hardly ever fall into one of the four corners. Center-weighted metering is also the preferred mode for portrait photographers, given that it ensures your subject is properly exposed without putting too much emphasis on the background.
Use center-weighted metering when you want to capture a brightly lit subject and want to get it properly exposed relative to the surrounding elements. This is also a great option when you want to photograph a subject placed against the sun, but still want to avoid burning the sky or capturing areas that are too dark.
3. Spot / partial metering
This mode gives you the most control over the exposure by accurately measuring the light from a very small part of the frame. Spot metering is very useful in photographing high-contrast scenes where the subject may otherwise be covered in very strong shadows or highlights.
Basically, the spot metering mode tells the camera to do its light metering from a very small ‘spot’ within the frame, which is very helpful in difficult lighting situations where the background is either darker or brighter than your subject.
This metering mode is very useful for shooting back-lit subjects, such as taking a portrait of a subject whose face is slightly darker. If you would have used a different mode, the result would have been a silhouette with very few details of your subject.
If the scene is darker or lighter than your subject, then spot metering will give you a very precise exposure, such as the example below:
This metering mode is also great for photographing subjects that are far off in the distance, especially when they are not taking up the entire shot:
Another great use Spot metering mode is for capturing the Moon. Since the sky is totally dark around the Moon, using this mode would allow you to capture the light reflected by the Moon. If you tried to photograph the Moon using matrix metering, you would get a bright circle and very little detail, which adds nothing to the enthusiasm you might have for the Moon.
What about exposure compensation
No matter what metering mode you use, there will be times when the camera’s built-in light meter would fail to properly expose an image. Exposure compensation is an easy way to fix the in-camera metering inaccuracies.
– Used when photos are too bright (-3; -2; -1)
– Used when photos are too dark (+1; +2; +3)
If your shot is underexposed (darker), use EC to increase the compensation level by a stop or two. If the photo is overexposed (e.g. when the sky has turned from blue to white), you can use exposure compensation to decrease the exposure and retrieve the details in your shot.
Snowscapes or beach scenes with bright sand will always require negative compensation of at least one stop, whereas a low-key image with predominantly dark tones will require positive exposure compensation.
So which mode should I use?
As with anything in photography, the answer is it depends. Always select a metering mode based on what you are planning to accomplish. Pick spot metering if there is something in particular in a frame that you want to highlight. Use matrix metering for any other type of images and if it doesn’t work for you, just switch to center-weighted mode and see if your results get any better.
Matrix metering works best with darker or flatter images, whereas high contrast scenes are best captured using the center-weighted metering. Leave the spot metering for backlit subjects and for when you have enough time to experiment. Metering is best learned with a lot of practice and many trial and error shots. Remember, matrix metering will help you to capture moving subjects, especially children, animals or street shots taken on the go.
Once you have the know-how, you can begin to experiment and get even more creative. The better you understand the different metering modes and the situations for which they are best suited, the more prepared you will be to switch modes when the time comes.