During last week’s Photo Tip Thursday I was asked a question about what I meant when I was talking about metering modes and how they “meter light”. So for this week’s tip, I thought I’d try and explain them a little more clearly with some visuals too to help better explain what it is that I’m talking about.

Metering refers to the camera measuring how much light is entering the lens and hitting the image sensor. It doesn’t have anything to do with focusing. The sole purpose of metering is to determine the proper shutter speed/ISO needed to properly expose your subject in the photo. When a camera meters, it samples the amount of light from several areas of the photo, and by a mathematical formula, averages these amounts out to tell you the current exposure of the photo you’re about to take, allowing you to make adjustments so that whatever you’re trying to photograph is properly exposed. Your photo’s exposure value can be seen in the light meter that I’ve mentioned a few times before.

The nifty thing is you can change how a camera meters, a.k.a. where it samples light from to get the average exposure allowing you to adapt for some tricky lighting situations. There are three basic metering modes on most cameras that I’ll go into detail about below. I’ll also show the same picture with each mode that you’ll notice is overlaid in varying areas with a red color. The red represents the area that the camera is sampling light from. Areas of darker red mean that the camera is sampling more heavily from these regions {giving them more weight when determining the average}, and conversely, areas of a lighter red color are sampled less heavily {giving them less weight when determining the average}. So let’s begin.

This is our what our sample image would look like through the viewfinder.

1. Evaluative Metering {Canon}/Matrix Metering {Nikon}: This metering mode samples light from all areas of the viewfinder to determine the proper exposure for your subject. If you’ll notice, the whole image is shaded evenly with a red color, meaning that the camera samples with equal priority in each of these areas, both on Grace and her outfit, and the bright background behind her.

Evaluative/matrix metering is the default metering mode for all cameras. It works well when the lighting in all areas of the photo is similar, such as an evenly shaded area. It DOES NOT work well for backlit subjects! The reason being is that the camera samples light from the really bright background areas, as well the subject whose front is shaded from the sun and much darker, and tries to average them. This nine times out of ten results in dim, poorly exposed photo. Do yourself a favor, switch out of this mode as soon as you can.

2. Center-Weighted Metering {Canon & Nikon}: This metering mode samples light from a circular region around the center of the image, giving more weight to the areas closer to the center. This is my personal favorite metering mode because it works well for just about every type of lighting condition imaginable and my camera is constantly set on it.

The great thing about this mode is that it samples light primarily from the subject {both skin and outfit}, and not the background, meaning that the average exposure is determined by the lighting of your subject and outfit, not the background. This is essential for backlit subjects! Remember, when shooting fashion photos, showcasing the outfit properly is the most important part, and this is the metering mode that gives all the priority to the outfit being properly exposed, so that’s why it’s my personal favorite.

3. Spot Metering {Canon & Nikon}: This last metering mode samples light from a very small area {maybe 2-3% of the area of your viewfinder} in the center of your viewfinder to determine the average exposure. It works similar in a way similar to that of the center-weighted metering mode, but it is much more specific.

You might be thinking that this is also a good mode for properly exposing a backlit subject, but often times its great specificity tends to come back and bite you in the face. For instance, if your subject is wearing a very dark top, then when the camera samples from this area alone, it might think you need to brighten the image when you actually don’t, resulting in an over-exposed photo.

Moral of the story, when shooting outfit photos, stick to the center-weighted metering mode. It’s more accurate, more reliable, and more adaptable than either of the other two modes.