DSLR Basics: Understanding Camera Metering Modes

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Have you ever thought about our situation if there were no metering sensors in the Camera?

Camera metering does the most critical job of the image making process, yet ignored by many.

It measures the brightness of the scene to make (or to aid in making) an exposure!

Before getting into Camera metering modes, it is very important to understand the basics of light metering. It will give you a glimpse about the light meters and their usage.

All the modern Digital Cameras use  built-in light metering sensor.

Light metering sensor, measure the brightness of a given scene and chooses the required Aperture, Shutter Speed and ISO values to make a proper exposure.

Light Meters

Light meters generally fall into two categories:

  1. Incident-light meter
  2. Reflectance-light meter

Incident-light meter, measures the brightness of the subject based on how much light is falling on the subject. It gives the accurate exposure since the incident light will be same no matter the reflectance of the subject.

However, the measurement is taken by placing incident light meter in place of the subject, which makes it impractical to use in the camera.

Reflectance-light meter, measures the brightness of the subject based on reflected light by the subject. Because it measures the reflected light, it is possible to measure the brightness from a distance.

Camera Metering Uses Reflectance-light

All the camera metering sensors uses reflectance-light meter. Reflected light meters are calibrated to calculate the proper exposure for normal subjects of an average brightness.

The metering sensors are generally tuned based on 18% reflectance theory. As we all know, pure white reflects 100% of the light and pure black reflects 0% light. But the mid gray reflects 18% of the light.

So, the camera metering sensors are tuned to this average reflectance value.

For most of the lighting conditions and scenes, the camera metering is tuned to give proper exposure measurements. However, the exposure calculations can go wrong when there is a very bright (Egret) or very dark (Common Raven) subject filling the frame considerably.

Camera Metering Modes

Camera Metering modes are probably the most neglected ones. Mostly because the default camera metering mode does a very good job.

Understanding them will definitely help you to make better images under all circumstances.

An image is divided into multiple portions (or zones) to find out the brightness in the entire scene. Based the metering mode chosen by the user, metering sensors will either use a small number of portions (or zones) or the all the portions/zones to measure the brightness.

In order to make it easier for user to expose properly for all the different lighting conditions, Camera manufacturer provides few metering mode options like:

  • Spot Metering Mode
  • Partial Metering Mode (only in Canon)
  • Center-Weighted Average Metering Mode
  • Evaluative (Canon) or Matrix (Nikon) Metering Mode
Canon and Nikon DSLR Camera Metering Modes - Spot, Partial, Center-Weighted, Evaluative or Matrix metering mode

Image showing various Metering modes supported by Canon and Nikon Cameras

Spot Metering Mode

As the name suggests, the brightness is measured only in one spot (or one zone) in the entire image. Depending on the camera make and model, it may be just 3 to 5% of the image area.

Canon and Nikon DSLR Camera Metering Modes. Image shows Spot Metering Mode.

Image showing Spot metering mode. Only 3 to 5% of the entire image area is measured for brightness. Some Canon Cameras measure only in the center. Otherwise, Nikon and high-end Canon cameras measure it around the active focus point

Spot metering mode is useful in many scenarios like:

  • Getting precise exposure on the main subject only
  • Bright subject  in the dark background (ex: Great Egret with shaded background)
  • Dark subject in the bright background (ex: Common Raven with bright sky in the background)
  • Measuring the brightness in different parts of a landscape scene to achieve perfect exposure using zone system

Spot Metering mode on Nikon DSLRs is based on focus point selection. Which means, you can expose properly for the the main subject of interest which you are focusing on.

It seems that spot metering based on focus point is available only on Canon 1DX series DSLRs. All others models will meter only the center of the frame, no matter where the focus point is set.

You may have to check how it works on your DSLR and use it accordingly.

Partial Metering Mode

Partial Metering mode measures slightly larger area than the spot metering mode. It meters approximately 10% of the image area in the center. It is only available in Canon cameras.

Canon and Nikon DSLR Camera Metering Modes. Image shows Partial Metering Mode.

Partial Metering mode covers slightly larger area than Spot Metering mode. It covers approximately 10% of the image area in the center.
This mode is available only in Canon models

Partial metering mode could be used in the similar scenarios to that of Spot metering like:

  • Getting precise exposure on the main subject only
  • Bright subject  in the dark background (ex: Great Egret with shaded background)
  • Dark subject in the bright background (ex: Common Raven with bright sky in the background)

You can choose either Spot metering or Partial metering mode depending on how big is your subject in the frame.

Center-Weighted Average Metering Mode

In center-weighted average metering mode, the metering sensor calculates the average brightness of the entire scene but gives maximum weightage to the center as opposed to rest of the image area.

Basically, center-weighted average always measures the brightness of the entire scene no matter what the scene is. Center area and the weight factor may vary for different make and model.

Canon and Nikon DSLR Camera Metering Modes. Image shows Center Weighted Average Metering Mode.

Center-Weighted average metering measures the brightness of the entire image area no matter which focus point is selected. It is suitable for scenarios where the light is evenly distributed

Center-Weighted Average metering mode is useful for scenarios like:

  • Scene where the light is well distributed and diffused, like cloudy days
  • Scene where the main subject of interest is framed in the center, like portraits

Matrix Metering (Nikon) or Evaluative Metering (Canon) Mode

Matrix or Evaluative metering mode is an intelligent way of knowing what a scene is composed of, based on heuristics (or prior patterns). It measures the brightness of the scene at multiple points (or zones) in the image and evaluates the optimum exposure that is needed to make an image.

Matrix or Evaluative metering is linked directly to the active autofocus point. Camera meter measures the brightness of the area around the autofocus point and compares it with the rest of the scene to come up with an appropriate exposure.

It also takes into account the subject brightness, contrast, color information, etc to make an accurate measurement of light for a given scene.

Canon and Nikon DSLR Camera Metering Modes. Image shows Evaluative or Matrix Metering Mode.

Evaluative metering (for Canon) or Matrix metering (for Nikon) mode measures light around the active focus point and compares it against the brightness of rest of the photograph to come up with accurate exposure.
This is the default metering mode in Canon and Nikon cameras

Due to above said qualities, Matrix or Evaluative metering mode is the default metering mode in the digital cameras.

You can use it in all the situations except the one described in Spot or Partial metering mode.

Conclusion

Camera Metering mode is the most important aspect of a Digital Camera. We set the exposure based on the camera light meter’s reading.

Imagine a situation if you were to carry a light meter on your own!

As always, try to use each of these metering modes and get to know how the meter behaves in different lighting conditions. Since there are only 3 or 4 modes, it is easier to understand their effects thoroughly.

Remember to check the light distribution using the Histogram to make sure that the exposure is correct. Learn how to achieve proper exposure using Histogram.

Let me know if you have any questions. If you think I missed out something, please feel free to mention it in your comments. It will be very useful to hundreds and thousands of visitors.

If you find this article useful, don’t forget to share it with your friends.

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27 Responses to DSLR Basics: Understanding Camera Metering Modes

  1. Nikhil February 9, 2014 at 2:23 am #

    Very useful to know!

    • Prathap February 9, 2014 at 12:01 pm #

      Thanks for letting me know Nikhil.

  2. Mahesh February 9, 2014 at 11:07 pm #

    valuable informative articles.

    • Prathap February 10, 2014 at 11:31 am #

      Thanks Mahesh. I hope it was simple as well.

  3. Dattatreya March 16, 2014 at 2:30 am #

    Useful articles.

  4. Janet April 4, 2014 at 4:54 pm #

    Great explanations, very informative. Thank you for sharing.

  5. Chandrasekhar January 23, 2015 at 2:04 am #

    Quite simple and understanding explanations. Thank you very much for sharing.

    • Prathap January 24, 2015 at 1:21 am #

      Thank you so much for the kind words Chandrasekhar.

  6. Urmish April 24, 2015 at 11:38 am #

    I am learning DSLR and your articles are really useful in understanding various topics. Thank you very much

    • Prathap April 25, 2015 at 5:18 pm #

      My pleasure! Urmish. I am glad that they are helpful.

  7. suresh raut May 24, 2015 at 7:42 pm #

    I would like to have your blogs on photography which mention in your category.I am ready pay in Rs in India.

    • Prathap May 24, 2015 at 10:11 pm #

      Hi Suresh, I didn’t understand. Could you please write a detailed mail using the contact form?

  8. Nze Anizor June 18, 2015 at 5:15 pm #

    Thank you, Sir! Quite helpful.

    • Prathap June 19, 2015 at 4:35 pm #

      My pleasure! Nze Anizor. Thank you!

  9. Shalabh October 18, 2015 at 10:01 pm #

    Hi,

    Thanks for the tips, but I am totaly a novice right now. Can you please let me know what settings to use in landscape photgrapphy with snow clad mountains in backdrop and what manual settings for Milkyway galactical photography . i am using Nikon d7000 with 18-105mm Lens.

    Shall be thankful to you for tips and settings suggesntions.

    Regards
    Shalabh

    • Prathap October 21, 2015 at 10:19 am #

      Hi Shalabh, Thank you! If you read my blog posts you might realize that I don’t give particular settings for a particular scene. That’s because every scene is different so is every setting for that scene. It simply depends on the scene. If you understand and practice the basics of metering quite well, you will be able to make the right judgment.
      Just remember this simple rule of thumb. No matter what settings you use, just make sure to get the exposure right. Because finally everything boils down to one thing and that’s EXPOSURE. Simplest way to know is to check your histogram.
      http://www.naturephotographysimplified.com/tips-and-tutorials/understanding-histogram-in-photography-achieve-proper-exposure/
      I have really no idea on photographing Milkyway. Sorry about that!

  10. suresh raut November 8, 2015 at 5:18 pm #

    Let me take this oppertunity to wish happy diwali.may diwali bring u lot of joy’ happiness good health and pease of mind. I have some problems when focussing any subject. and recomposing the given shot.

    • Prathap November 14, 2015 at 10:50 am #

      Thank you for the wishes! Suresh Raut.
      It’s called focus locking technique. Follow below steps to get the best results:
      1. Focus on the subject
      2. Hold AF lock button on the back of your camera. If you don’t find one in your DSLR, check the camera guide for AF lock button.
      3. Recompose
      4. Click the shutter keeping the AF lock button pressed at the same time.
      5. Release the AF lock button after taking the photo.
      I hope this helps.

  11. Cynthia February 8, 2016 at 9:31 pm #

    This is the best explanation for which metering modes to use in any given situation! Thank you!

    • Prathap February 9, 2016 at 11:34 am #

      Thank you so much! Cynthia.

  12. Anil Khan May 13, 2017 at 12:52 pm #

    Hi Prathap!

    I still can’t figure out the purpose of the metering facility provided for the DSLR. I am a beginner in photography and using a Nikon D5100. My question is, when using the P, S or A modes, all we need to do is just set any one of the metering modes on so that the camera takes the reading to automatically adjust the lighting to obtain a good picture? Or, do we have to adjust the lighting using the exposure compensation mechanism no matter which metering mode is on?

  13. Evarts May 19, 2017 at 7:22 pm #

    What is the best metering mode and camera setting for wildlife (Bird) photography?

  14. Bhaskar May 28, 2017 at 1:47 pm #

    Very nice 👌

  15. Bhaskar May 28, 2017 at 1:51 pm #

    Did not understand this :
    Measuring the brightness in different parts of a landscape scene to achieve perfect exposure using zone system

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