Some Notes on Canon’s Evaluative Metering

September 20, 2012 by
Filed under: Features 

I’ve been shooting with Canon SLRs for a long time, and for the most part, I’ve always been pleased with the camera’s metering. Granted, I can never remember which icon corresponds to which metering mode, but now that I keep the PDF of the manual on my phone, I can always look it up. During a recent shoot, though, I came across a curious detail about Evaluative metering that I never knew – one that can dramatically alter metering behavior in certain situations.

Consider the following:

I shot this image with a Canon 5D Mark III. Metering was set to Evaluative and focus was set to automatically select a focus point. The camera set focus on the black bowl, and metered at 1/40th of a second at f4.

But watch what happens if I manually select a focus point. In this image, I manually set a single focus point on the black bowl.

I’m still in Evaluative metering, but with my focus point manually set, the camera has metered entirely differently. It now says 1/30th of a second at f4.

Now watch what happens if I move the focus point to the white bowl:

Again, while I’m still in Evaluative metering, the camera has metered completely differently. It now comes in at 1/100th at f4.

I’ve always assumed that Evaluative metering was a straight matrix metering mode. That is, that it divides your scene into a grid, meters each cell of the grid, and comes up with an overall metering. In fact, it does do that, but if you manually select a focus point, then it gives more metering weight to the area around that point.

I usually keep my autofocus set to a single point in the center of the image, and I usually use Evaluative metering. I’ve been assuming all along that I was getting a matrix type metering, but what I’ve really been getting is more of a center-weight metering.

I probably should have been paying more attention to the name. If it was a straight Matrix metering mode, Canon probably would have named it as such. Instead, they called it Evaluative, and I assume that’s because it evaluates metering based on more than just its matrix analysis – it also includes focus point in its considerations.

Now, I’ll be honest, I don’t think this has really ever caused me a problem, but in a situation like the one shown above, your metering will get very screwy. I’m simply presenting this information here so you don’t get confused if you find yourself shooting a boring picture of black and white bowls.

One other note: when you select Spot metering, metering does not follow your focus point. Instead, Spot metering always reads the very center of the frame. This is something that possibly could get you in trouble if you tend to work a lot with the Canon Spot meter, so be careful.

Note that none of this is specific to the 5D Mark III. This is simply how Canon’s metering and focusing works on their SLRs.

Comments

12 Comments on Some Notes on Canon’s Evaluative Metering

  1. Omar on Thu, 20th Sep 2012 12:56 pm
  2. So this means that we should stick to center point while we have spot metering all the time, and recompose instead of moving the focus point? And switch to evaluative to actually move the points from the center? If the answer is yes, then makes sense to if I understood well what you wrote…

  3. Marc M on Thu, 20th Sep 2012 2:05 pm
  4. Interesting, thanks! Does the same thing happen at smaller apertures? I like to use fixed center pjont autofocus also. What a metering mode other than evaluative give more consistent exposures with changes in focus point?

  5. Wm. Reed Lovick on Fri, 21st Sep 2012 8:19 pm
  6. That IS interesting. I also find the 5DIII to be very sensitive to light.
    What lens are you using for these images ( f4. 28 – 105 L )?

  7. Richard Stern on Sat, 22nd Sep 2012 9:46 am
  8. I bought your book Complete Digital Photography 7th edition.
    I am working through the book. Many of the files have broken links. It would be great if you could fix these. I was able to download some of the files from the 6th edition link.
    I can not download these:
    _mg 3501.CR2
    underexposed.jpg
    fig 20.14 – see for yourself.psd
    and most of the files from Chapter 21 and later.

    Sincerely,

    Richard Stern

  9. Brian R on Fri, 28th Sep 2012 5:06 pm
  10. About your spot metering comment – I’ve been into photography for only about a year and initially assumed (given that I’ve never developed the ability to completely memorize owner manuals) that when I push shutter button halfway to lock focus and then re-frame with my Canon I’ve locked exposure as well; I eventually noticed weird exposures in certain situations when trusting the camera in various modes, leading to diminishing confidence. So I’ve taken the plunge into manual mode (usually with AF and auto iso) in most circumstances and have been happy (I find that it’s like having Av and Tv flex simultaneously) and, I think, more skilled (being forced to slow down and think through the shot more.) I do stay in P mode in walk arounds just in case of instant opportunities, but as soon as I see opportunities that will last beyond the moment I revert to M.

  11. Dean Walker on Fri, 5th Oct 2012 1:59 pm
  12. Hi Ben, your training videos on Lynda.com have been a terrific help. I have worked through all of them. These courses are among the very finest online training I’ve seen–detailed, in-depth and well structured for the student. (Your colleague at Lynda.com, Chris Orwig, does a great job as well, though on the development side).

    I wonder if you would consider offering a comparable course on Canon speedlites, at Lynda.com or through your own website. Most flash lighting training programs I’ve been able to find are really for Nikon users. Other resources I’ve seen (e.g. Canon Learning Center) sort of assume you know how the speedlite technology works before you start. If you were to design a Canon-oriented course, I think it would address an area of need for quite a few people..

    I am looking for Canon on/off-camera flash training that will take me from the basics through to fairly high-level implementation in some detail–a few hours long, not a few minutes. My gear is the 5D Mark II plus 580, 550 and 430 speedlites.

    If you have a suggestion, I would be excited to hear it.

    Many thanks. Your work has been of genuine assistance to my wife and me.

    Dean Walker

  13. Steve Herried on Tue, 9th Oct 2012 8:38 pm
  14. I looked at the Canon Learning site at Canonusa.com and this is what I found as far as what evaluative meters. Check out the link and look at the pink squares that are highlighted when the left most focus point is activated. So basically it doesn’t read the whole screen that we see, just a portion that it located nearest the most important part of the focused area. Check out this link.
    http://learn.usa.canon.com/resources/photos/articles/photographing_snow/Metering-Zones.shtml

    Steve

  15. Steve Herried on Tue, 9th Oct 2012 9:30 pm
  16. Adding to what I said previously. when you put the focus point on the black object, the metering probably didn’t include most or not any of the white bowl of the scene thus affecting the reading.

  17. Henrik Helmers on Thu, 25th Oct 2012 2:43 am
  18. That’s very useful to know! I need to practice shifting my focus point around. Do you know if it changes depending on how many focus points you keep available or if it only uses the points where it locks down focus?

  19. Miguel Torres on Sun, 14th Apr 2013 9:46 pm
  20. I have a questions that has nothing to do with metering, but I thought I could ask you here because I have no other way to contact you. I have seen these two course in LYNDA: Shooting with canon 60D and shooting with Nikon D3000. So I know you know both cameras very well. I am planning to buy one of them soon but I cannot make my mind and I’d like to have you thoughts? Which one would you recommend? I’ve heard the nikon is better for pictures and the canon better for video but I don’t know if that is true. I wish there was a camera in this price range that was better at both. Also, would you recommend buying a refurbished camera with extended warranty for a full year? thanks and sorry for posting this question on this section.

  21. Miguel Torres on Sun, 14th Apr 2013 9:46 pm
  22. Sorry I mean nikon d7000 not d3000

  23. Baz Petch on Mon, 14th Oct 2013 2:03 pm
  24. Hi Ben,
    Many thanks for all the time you have spent and the willingness you have to help and teach others, I have learned so much from your book and also your Lynda.com courses, with your help I am becoming a better photographer, and I love it…

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