What are Camera Metering Modes?
Camera metering modes are a way for you to tell your camera how much of the scene is to be considered for calculating the appropriate exposure value. In other words, metering modes play a role in determining the automatic aperture and shutter speed utilized by your camera. Needless to say, metering modes are applicable when you’re shooting in one of the program modes. If you’re shooting in manual mode, you can dial in the exposure value yourself, without having to depend on the camera’s light meter.
Why is it important to understand how camera metering modes work?
Understanding camera metering modes is pertinent because it is an effective way of measuring the amount of light reflecting off of a surface. That is if you’re not using an external light meter.
I will not be touching on external light meters in this discussion, but for the sake of information, I would like to mention here that external light meters are by far the most accurate tools for metering a scene and therefore widely preferred by professional photographers.
Every camera comes with one or multiple modes of metering. Depending on the camera that you’re using, you may even have three or four metering modes.
Metering Modes on Canon Camera Systems
Canon’s evaluative metering system is more or less similar to Nikon’s matrix metering (listed below). In this metering mode, the camera takes an average readout of the whole scene and then dials an exposure value that’s going to give a decent picture in most kinds of lighting. Evaluative metering works in a large number of shooting situations, including backlit situations.
Partial metering mode uses a sample area that is a lot smaller than evaluative metering. It tends to vary between 5% to 6% of the viewfinder area and therefore is more effective when you need to sample a smaller portion of the frame.
Partial metering mode is ideally suitable for shoots where the subject is backlit and therefore preference has to be given to the area dominated by the subject, disregarding the rest of the frame.
In the spot metering mode, a small part of the frame, no bigger than 1.3%, is used to meter the scene. Spot metering coincides with the active autofocusing point, and therefore, if you move the AF point around, metering calculations will change depending on the brightness levels.
Spot metering is by far the most accurate of metering modes. It gives you a precise reading of the scene if you know where to place the AF point. It’s also the most difficult metering mode to work with because it can easily get things wrong if you point your active focus point on something very bright or very dark.
Spot metering is the preferred way to go when center-weighted or matrix metering is unsuitable for a particular scene. It is also the preferred metering mode when the subject you are trying to photograph occupies a very small part of the frame.
Theoretically, you can use spot metering for landscape photography as well. This is because a scene may have wild variations in light levels and averaging it out may not be the best way to approach it. Also, when you do not consider the highlights you risk blowing them out and thereby losing any chance of recovering details.
With spot metering, you can focus on the highlighted areas, meter for it, lock exposure, refocus, and then take the shot. This way you retain all the details in the highlights and, going by today’s camera standards, it will not be a difficult task to salvage details from the shadow areas.
One thing to note about the spot metering mode is that if you’re using auto-area AF the camera will use the center focusing point to meter the same. This happens with Nikon systems and can be a very frustrating experience if you are not sure if you have the auto area AF switched on.
Center-weighted Average Metering
Center-weighted average metering is similar to partial metering in the sense that the sampling area is more focused. However, there are a few differences between center-weighted average metering and partial metering. Most of these stem from the fact that the background is also considered for exposure calculation in center-weighted average metering, albeit to a lesser degree.
The other difference between the center-weighted average metering and partial metering is that the metering sampling area is the center of the frame.
This is the reason why center-weighted average metering is ideally suited for portrait photography when the subject is standing in the middle of the frame.
Metering Modes on Nikon Camera Systems
Nikon systems traditionally had three metering modes. However, the latest cameras from Nikon come with four metering modes:
Matrix metering, which is a Nikon term, is pretty much the same thing as the evaluative metering mode that Canon camera systems use. If you are using a G, E, or D-type lens then this metering mode will also utilize distance information using the 3D color matrix metering III. With non-CPU lenses, however, 3D distance information is not utilized for metering.
Again, center-weighted metering is pretty much the same as the Canon system I just explained. Only the sampling area is a little different.
Nikon’s spot metering system is similar to the one I explained above, except that in this case the sampling area is 1.5% of the viewfinder area.
The only difference between the Canon and Nikon metering systems is the highlight-weighted metering system which comes in the latest Nikon cameras.
In this particular metering mode, the camera gives the maximum amount of importance to the highlight areas, thus exposing the highlights. This directly benefits the photographer by not risking blowing out the highlights and retaining as much detail as possible in those areas.
The greatest advantage of a highlight-weighted metering system comes into play when you are shooting scenes with large variations in brightness levels. Modern cameras have an excellent noise-to-signal ratio. With the majority of modern interchangeable lens cameras, you can drag the exposure slider in post-processing and retrieve details from the shadows without adding noise. In other words, even if you underexpose the scene by metering for the highlights, you can retrieve details later on.
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Best Use Case for Each Metering Mode
Let’s discuss in further detail the best way to utilize each of the metering modes I have mentioned above.
When to Use Evaluative/Matrix Metering Mode
Ideally, you should be using matrix metering when there is a very low difference in lighting levels across the frame. In my experience, I’ve seen matrix metering give me the best results when I’m shooting landscape, street, and travel photos.
This is the default metering mode preset in your camera, so most photographers start using it without even realizing that the metering mode is active. It’s only when they don’t get the desired results in certain conditions that they start realizing something may be amiss with the metering mode.
Although I use the word “amiss”, there is nothing wrong with using matrix metering most of the time. Most scenes don’t require the advanced input of other metering systems.
It’s only when your subject is backlit or when it’s occupying a small part of the frame and is differently illuminated from the rest of the scene that matrix/evaluative metering tends to get things wrong. Thus, many photographers will never have to venture beyond this mode.
When to Use Spot Metering Mode
As I mentioned above, spot metering is ideally suited to scenes where there are wide fluctuations in lighting levels and you want to meter off of something neutral.
Additionally, spot metering can be advantageous when a subject is backlit, for example, if you are photographing a subject that occupies a small part of the frame and is backlit.
Let’s say you are trying to photograph a bug. You get in close to the bug using a macro lens and then use the spot metering mode to meter off of the bug while disregarding the rest of the scene. That should give you an accurate exposure value.
Spot metering is also useful in a scene where there is a dominating amount of white and you want to properly meter for a darker color such as black or vice versa.
If you go for matrix metering in a scene like this the dominating white color will skew the metering system of the camera and make it underexpose the scene.
The reverse happens where there is a dominating amount of black in a scene and you’re trying to photograph something that’s predominantly white.
I have already mentioned above that spot metering uses the active AF point. So, if you have an off-center subject, spot metering will give you a better result than any of the other metering modes.
When to Use Partial Metering Mode
Partial metering mode samples a larger part of the scene compared to spot metering. So, this mode is better suited when your subject occupies a larger part of the frame than what can be managed with spot metering mode.
Let’s look at an example of a medium-sized bird. The bird will occupy a larger part of the frame than the aforementioned bug, considering that you’re using a telephoto lens and you’re trying to fill the frame.
If you use spot metering in a situation like this, you could perhaps walk away with a reasonably well-exposed photo. However, a better approach would be to use the partial metering mode because it brings into consideration a larger part of the subject and therefore gives you a better metering result and a more accurate exposure value.
When to Use Center-weighted Metering Mode
Center-weighted metering mode is always my choice for shooting portrait photos. It does a great job when the subject is at the dead center of the frame.
Remember, the major difference between the center-weighted metering mode and the spot metering mode is that in the latter you can move your AF point around and the camera will recompute the light value and give you a different meter reading for the active focusing point.
With center-weighted metering mode, preference is always given to whatever is at the center of the frame. This means that off-center compositions are a little difficult to achieve with this mode.
Because center-weighted metering emphasizes the center of the frame, it is also suitable for backlit subjects, such as when you are shooting at the golden hour and the sun is behind the subject. Center-weighted metering will expose the subject’s face while also taking into account the rest of the frame’s brightness levels.
When to Use Highlight-weighted Metering Mode
I’ve already mentioned the importance of the highlight-weighted metering mode in scenes that have strong highlights. This mode always does a good job of exposing the highlights, ensuring that they are not clipped and retain details.
However, the highlight-weighted metering mode does not apply to all kinds of shooting situations. For example, when you are photographing with harsh backlighting highlight-weighted metering will meter for the background and underexpose the subject.
Having said that, this metering mode is ideal when you deliberately want to capture a silhouette.
It can also be used when you want to use an external light source, such as a studio strobe or a flash, to illuminate the subject’s face. You can use the metric mode to expose the background and then add the flash to brighten the subject’s face.
Overriding the Camera Metering Modes
Despite choosing the most appropriate metering mode for a shooting situation, there may be instances when the camera does not get the exposure just right. It may become necessary to override what the camera metering mode is suggesting as the correct exposure value.
Let’s look at some of those situations.
Beyond the Camera Metering Modes
I always consider the camera metering modes to be a guideline rather than a compulsion. These days cameras come with amazing dynamic range. You can shoot at two, three, or even four stops underexposed and still be able to salvage all the detail in the shadow areas during post-processing in a way that negates the necessity of using the correct metering mode.
Highlights, however, are a completely different ball game. There’s really not much you can do if you clip your highlights during shooting and that is what necessitates using the right exposure value for your compositions.
As long as the camera’s built-in meter tells you that you are on or below the desired exposure value you should feel safe to shoot knowing that you can recover details during post-processing.
In any case, a lot of postprocessing happens despite using the right metering mode. Landscape, for example, is a genre of photography where photographers spend a considerable amount of time retouching and fine-tuning their photos.
Additionally, when you apply techniques such as high dynamic range by stacking multiple exposures you bypass the need for using the right metering mode. By shooting at different exposure values – above or below what is “appropriate” – you give yourself a lot of dynamic range to play with.
Generally speaking, the matrix metering mode works in most cases. So, if your subject is backlit, it’s better to use partial metering or center-weighted metering. You could theoretically use matrix metering for a portrait scene, but only when the background and the subject are uniformly lit.
Partial or center-weighted metering modes are well-suited for portrait photography. This is because there is a high possibility with portrait sequences that the subject is lit differently than the background. In a situation like this, metering for a smaller part of the scene which is dominated by the subject makes for a better metering approach.
Spot metering should be used only when you’re more confident with your metering exercises. This metering mode can be a little confusing to master at the beginning. This is because spot metering uses the active AF point to meter a scene. If your active AF point isn’t placed over something that’s of average reflectance (about 18% grey) then metering could be skewed, resulting in an overexposed or underexposed image.
Given the fact that modern cameras have a large dynamic range and we have access to a whole world of software tools, we can easily salvage details from shadow areas. In other words, we can always expose the highlights and pull the shadows during post-processing.
But even then, it is always recommended that you try and achieve an exposure that is as close to ideal as you can. The main reason being, if you’re shooting a lot of frames you will have trouble processing them afterward.
It will be time-consuming and even then it may not always be possible to salvage all your exposures. Getting the shot as close to what you want to achieve in-camera allows you to save a considerable amount of time and disappointment later on.
No, it isn’t. If you’re shooting in manual mode the camera will only let you know if and by how much you are off. If you look at the light meter at the bottom of the viewfinder you will notice that it will skew either left or right or stay at the center depending on the exposure values you have dialed in. The metering mode dictates the exposure value in all other shooting modes.
No, it isn’t. Metering modes can sometimes get it wrong. It partially depends on the photographer choosing the most appropriate metering mode for the scene but it also depends on the inherent technology that powers a camera’s metering mode. All cameras are programmed to look at things as 18% grey (middle grey), or of average reflectance.
If it finds a subject that is too bright it will underexpose the photo, and if it finds something too dark it will push the exposure to make the subject appear averagely reflective or middle grey. Plus, camera metering modes use the reflected light concept and not the incident light concept of metering, which allows for metering mistakes.
If you want to meter a scene accurately, try using an external light meter. These are a bit of an investment at the start of your career. But if you’re interested in using artificial lighting or shooting landscape photos a light meter will be a better bet than the built-in meter of your camera.