Metering Modes Explained

Posted By @ 9:00 on October 31st 2012
Category: A Beginners Guide, blog, Exposure, Metering Modes

MeteringModes

As we all know, digital cameras have a host of menus, buttons and dials, all of which relate to making different settings for our photographs. We’ve looked at some of these in past blogs – choosing the exposure mode, setting your white balance, and setting your file type, to name just a few.

Today we’ll have a look at metering modes. All DSLRs, and many compact cameras, will offer a choice of metering modes, usually Matrix, Centre-weighted, and Spot.metering

Matrix Metering:

this is also known as Evaluative metering. The camera meters across the frame, and then averages the overall brightness and chooses the exposure accordingly.

This metering mode will be fine in the majority of situations where there aren’t too many bright highlights or dark shadows, or backlighting, and the scene you are photographing is evenly lit.

Centre-Weighted Metering:

in this mode the camera still meters the entire frame, but assigns the greatest weight to an area in the centre of the frame. So this would be the mode to choose when your subject is in the centre of the frame, and you don’t want the exposure to be affected by very dark or bright areas around the edges.

Centre-weighted is often referred to as the classic metering mode for portraits, as it exposes for the subject rather than the background (assuming your subject is in the centre of the frame!).

However, this wouldn’t be the mode to choose if you’ve composed your picture with your main subject off-centre.

Spot Metering:

Here the camera meters only a small part of the frame. On my Nikon D700 the area is a circle 4mm in diameter – the exact amount will vary from one camera to another.

This means that you can take a very precise reading, getting the exposure correct for your subject, and ignoring brighter or darker areas in the rest of the frame.

It’s a good mode to choose when light is very contrasty, or to avoid a silhouette when your subject is backlit. It’s also good when your subject is small, as it allows for such precise metering.

Spot metering can become particularly important when photographing back lit portraits.  If you use Matrix/Evaluative metering in this situation you will end up with a well exposed sky and a silhouette of the person.  This is because the camera reads the sky as the dominant light source and stops down, under exposing your subject.

Spot vs Matrix

So although matrix metering will give you a good exposure a lot of the time, being familiar with the other metering modes gives you a little more control, and increases your chances of getting the exposure exactly right!

2 responses to Metering Modes Explained

  1. Trevor Farrell says:

    Oh dear, the author has clearly shown they have not got a good understanding of this, I would have hoped someone with some technical skills would have previewed it before allowing it to be posted :(

    Firstly, the metering mode sets the exposure, which is by a combination of shutter speed, aperture and ISO. So the three example photos leading the article should have different exposures to demonstrate how the different metering mode has effected the shot. BUT all 3 images were taken at 1/320, F/6.3 and ISO 200, so all 3 SHOULD be identically exposed. The differences are due to something else – change of lighting or post-processing perhaps?

    The author also has matrix and average metering confused. Matrix metering is where the manufacturer has programmed an algorithm to analyse the differences across the image to obtain an “intelligent” calculation of the exposure. What the author has called matrix metering is actually average metering, where the readings from the entire scene are simply averaged. Some manufacturers matrix algorithms are quite sophisticated and will do better in difficult lighting than the author implies.

    Many cameras have a partial metering mode as well. This is where the camera uses readings from approximately the centre 10% to determine the exposure. In contrast, spot metering uses approximately the centre 3%.

    Finally, being familiar with how to use the other modes will help the photographer get the best results, but equally important is an understanding of when not to use those other modes, which the author has neglected completely.

    Reply |
    • Sue Bishop says:

      Hi Trevor
      Many thanks for your comments on this. You are absolutely right about the pictures! I wrote the text for the blog, but the pictures and diagrams were added later by someone else, and I hadn’t previously seen them. But as you say, the captions on the pictures make no sense – either the captions are wrong, or the photos were post-processed differently.
      As far as the text is concerned, this blog was part of our “Beginners guide” series, and so I had purposely simplified it to some extent, and wrote only about the three metering modes that are usually available on most DSLRs. For this reason also, I didn’t go into the technicalities of algorithms or exactly how the camera calculates the exposure in matrix metering – it was meant to be an overview for beginners, rather than an in-depth piece!

      Reply |

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