What is metering?
DSLRs have a built-in light meters. They are reflective meters, meaning they measure the light reflected off people/scenes. They are not quite as accurate as hand-held (incident) light meters, but they do a very good job. Your meter itself is inside your camera, but you can see its readings through your camera’s viewfinder and also on your camera’s LCD. You can use your camera’s meter reading to determine if your settings for a given shot are good, or if you need to make any changes.
What kinds of metering are there?
The types of metering may vary slightly across camera brands and even camera models within the same brand, so consult your camera’s manual to confirm what types of metering your model has. Generally, however, cameras have most or all of the following:
- Evaluative/Matrix metering. In this metering mode, the camera takes into account the light in the entire scene. The scene is broken up into a grid or matrix by the camera. This mode follows the focus point on most cameras, and the focus point is given the most importance.
- Spot metering. This metering mode uses a very small area to meter from. In Canons, spot metering is limited to the center 1.5%-2.5% of the viewfinder (depending on camera). It does not follow the focus point. In Nikons, it is a very small area that does follow the focus point. This means that your camera is making its meter reading from a very small area and is not taking into account the lighting in the rest of your scene.
- Partial metering. If your camera has this mode, it is similar to spot metering, but comprises a somewhat larger metering area than spot metering (for example, on Canon cameras, it comprises about the center 9% of the viewfinder).
- Center-weighted average metering. This metering mode takes into account the lighting of the whole scene, but gives precedence to the lighting in the center of the scene.
OK, so how do I use these metering types? What are they good for?
Good question! In this blog post, I will talk about the two metering types that I use pretty much exclusively: evaluative/matrix and spot. I’m not saying that the other two modes are useless! I have just found that these two modes work for everything I need to do. I encourage you to read and learn from what I have to say but also encourage you to try other modes if you feel you might need something different.
This metering mode is kind of an “all-purpose” mode. It is what many people use exclusively when they are first starting out, and that’s OK. Evaluative metering is great to use when lighting is relatively even across a scene, such as in a landscape with no extreme frontlighting or backlighting, and is also good for most sports photography. Another area that evaluative metering is useful is if you are in a situation where you are combining ambient light and off-camera lighting. You can use evaluative metering to expose for your background, then use your off camera light to light your subject. Following are some examples of where evaluative metering is useful.
The previous is a landscape-type shot taken on a gray day. Lighting was mostly even, so evaluative metering worked here. Evaluative metering also works on sunny days for the most part, as long as your sun isn’t too low in the east or west and you’re not shooting directly into the sun.
Spot metering is the metering mode that I use much of the time. I use it for most of my natural light portraits, but it is quite versatile and has other uses as well. As I mentioned before, spot metering uses a very small portion of the sensor to meter. This means that you can meter specifically off your subject to expose correctly for them, which is great in tricky lighting situations. Spot metering is what you want to use if you are shooting backlit shots with natural light and you do not have a flash or reflector. Meter off your subject’s face (I generally meter off the brightest part). If you play around with indoor natural light and spot metering, you can get some really lovely photos with illuminated faces and darker backgrounds. One other situation where I find spot metering helpful is with sunrise or sunset silhouette shots. I spot meter just to the right or left of the rising or setting sun to get my settings. Keep in mind that if you have a Canon camera or any other brand that spot meters at a set viewfinder area rather than following the focus point, you will need to meter using the center area of the viewfinder, then recompose, keeping your settings, and take your shot.
You may currently shoot using evaluative metering and wonder what the difference is if you are using spot metering. Below are two shots, SOOC (straight out of the camera). The left shot was taken using evaluative metering, where the camera is metering using the lighting of the whole scene. The right photo was taken using spot metering, metering off the pumpkin. The camera is taking into account the light reflected off the pumpkin only in the right photo. See the difference? The trade off is that your background may be blown out, but your subject will not be dark.
A couple of examples of photos using spot metering:
Do I have to use my camera in manual mode?
No! Your can use metering in aperture and shutter priority modes, too. You will just need to use the AE (autoexposure) lock feature to lock your settings if you need to recompose your shot. Your camera meters in all modes, even auto, but in the auto modes, your camera chooses the settings based on metering rather than you being able to choose or manipulate settings.
My camera doesn’t have spot metering. Can I still take backlit photos?
Of course. There are some camera models that may not have spot metering but do have partial metering. On those models, use partial metering for similar results. You may need to play around a bit to see what works best for your camera.
My camera’s meter is showing a correct exposure, but my photo looks too dark/too bright.
As mentioned in the beginning of this post, reflective meters aren’t perfect, but they are close. The most important thing when you are shooting is to check your histogram to be sure your exposures are good. You will learn how your camera behaves in different situations after awhile (for example, I shoot at least 1/3 of a stop overexposed on all my Canons, and that can increase depending on the situation). If you are shooting in manual mode, you can choose to increase or decrease your aperture, shutter speed, or ISO based on the results you are getting. If you are shooting in aperture or shutter priority mode, you can use exposure compensation to tweak your exposure.
As with all things photography, practice makes perfect!
Amy Short is the owner of Amy Kristin Photography, a portrait and maternity photography business based in Wakefield, RI. She also loves photographing the local landscape in her off hours. Check out her website or find her on Facebook.
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