Learning To Leave The Matrix – A Tip On DSLR Light Metering

In photography, light is everything. Understanding how your camera reads light and determines correct exposure is the most important thing your camera does, yet it is also one of the most misunderstood. Your camera has different ways that it reads light by using an internal light meter and, depending on which metering mode you have your camera set on, it determines the correct exposure. For the most part, the metering mode is untouched and buried in the camera settings because, when you’re in the Matrix, life is good. Matrix is the default metering mode for all modern Nikon DSLR camera bodies (Evaluative Metering for Canon) and is often never changed. Actually, it’s recommended by many that you not change it because it works so well–but that’s not always the case. I’m going to explain a little bit about leaving the Matrix default mode and why you would want to such a crazy thing. First, I’m going to do a quick explanation about what metering is.

Metering has everything to do with exposure and understanding how your DSLR meters will help you understand a little bit more about how your camera determines the correct exposure when taking a picture. All modern DSLRs have metering modes–modes which determine how your camera goes about determining the correct shutter speed and aperture by reading the amount of light that goes into the camera. Life is much easier today with our fancy and expensive DSLRs compared to the old days when cameras were not equipped with a light meter. We no longer need a hand-held light meter to determine the optimal exposure. Today, every DSLR has integrated light meters that determine the optimal exposure via three different metering modes:

1. Matrix (NIKON) / Evaluative (CANON)
2. Center-Weighted
3. Spot (NIKON) / Partial (CANON)

Whether you shoot in Manual Mode, Shutter Priority, Aperture Priority, or Program Mode, it’s the camera’s integrated light meter that automatically adjusts the settings to give you what it feels is the correct exposure. The only problem is that even though it can read the amount of light, it can’t read your mind. Therefore the exposure it thinks is correct might not be the exposure you are looking for. When you have different objects in a scene with different light levels and light sources, it can become challenging and even frustrating if you don’t understand how your camera is metering. By default, your camera will take a reading of the light levels in the entire frame and will determine what it thinks is the correct exposure that will balance the bright and dark areas of the image. Sometimes it’s the dark areas that we want to brighten and the bright areas that we want to be dark and making adjustments to the shutter speed or aperture to correct this will end up under or over exposing the image. This is when you may want to try a different metering mode but you need to know how each mode takes its reading. You’re also going to need to know where to make the change in the camera since it can be buried in the menu in a lot of consumer-grade cameras (don’t worry, I have a solution for this at the end).

What is Matrix or Evaluative DSLR Metering?

Matrix or evaluative metering divides the frame (what you see when looking through the viewfinder) into zones which are then analyzed individually for light and dark tones. It reads the information in each of the zones, looks at the point at which you focus, and marks it as more important than all the other zones. There are some other variables that are thrown in the mix depending on the camera manufacturer but, for the most part, that is it. This mode will work flawlessly for most of your photography.

What is Center-Weighted DSLR Metering?

Center-weighted metering evaluates the light in the middle of the frame and its surroundings and ignores the corners. Compared to Matrix Metering, Center-weighted Metering does not factor in the focus point you select, it only evaluates the middle area of the image.

What is Spot or Partial DSLR Metering?

Spot or partial metering evaluates ONLY the light around the focus point you select and ignores everything else. It will take a reading on the single zone that surrounds the point of focus you choose, and calculate exposure based on that. No matter what else is going on in the frame, your camera’s light meter only cares about the focus area. Remember this mode–this is the one that will make you leave the Matrix.

Now that you have a better understanding of how your camera determines the correct exposure, you can see why the default setting is usually good enough for 99% of your photography. As a photographer who does a lot of portrait work, engagements, weddings, etc., things can get a little tricky and there are times when I need to leave the Matrix. I love shooting in natural light and when Matrix metering wasn’t giving me the exposure I wanted in certain situations, especially those where my subjects had the sun behind them, late in the day, throwing a flash in for fill light seemed to be the popular answer. True, this can be done, and I’ve done it, but I don’t always carry a flash with me, and that’s not always the look I’m going for. So when I struggled early on with situations like this, I turned to my metering modes.

I love shooting late in the day, not only the “golden hour”, but the last few hours of the day. I love shooting with the sun back-lighting my subjects, often right above and behind their heads. When my camera is set on its default Matrix metering, and I focus on my subject’s face, it takes a reading of the entire frame. When it does this, it tends to severely under-expose the subject. This is where a lot of photographers suggest turning to a flash to add fill light. Instead, I stick with natural light, keep my flash in my bag, hold down a single pre-programmed button to take me out of the Matrix. I have a button on my camera assigned to Spot Metering, rather than having to take the time digging through menu options. When I hold down the button, my metering mode is changed from Matrix to Spot. By simply switching to Spot Metering, my camera will take a light reading on the focus point of my subject’s face and ignore everything else in the frame. Take a look at the shots taken below from a recent engagement shoot on the beach. The first images were shot with Matrix Metering and then the second shot using Spot Metering, both are straight out of the camera. You can see how much of a difference it makes. When there is a severe difference in light, like the images below where the bright sun is behind the subjects, there can still be a slight under-exposure but you will have a better chance of pulling out the detail and just bumping up your shadows in post to get the image you want.

Matrix Metering takes into account your entire scene, making back-lit shots trickier.

Spot Metering – We lose some information in the sky but our subject is better exposed.

Matrix Metering – Filling with flash is ideal here but sometimes you are out in the field without one.

Spot Metering is a great option for narrowing your light meter to a particular subject.

Matrix Metering works excellently and, because it works so well, metering is often taken for granted and there are a lot of photographers out there that don’t completely understand how it works. A lot of DSLR camera bodies have the metering option buried in menus, which can make it not only a headache to try and change on the fly but also time consuming. The good thing is most cameras give you the option to set a “favorites” menu, which you can access pretty quickly. Or, like with a lot of Nikon cameras, you can assign certain buttons on the body itself to do certain things. I have my DOF Preview button configured to take me out of the Matrix and temporarily change to Spot. Give it a try on your next shoot. Don’t ever be afraid to try out new things like this–you may surprise yourself with the outcome.

See more examples of metering modes in action and how they can better serve you in Metering, Exposure Compensation, and Focusing Tips for Covering Events.