What They Do and When You Should Use Them
This is the most complex and modern way of metering a scene, through matrix metering. It collects data from across the entire frame and even gives priority to your focus point.
The camera will look at a scene. It will see a really bright area like the sun, and take that into account when trying to work out the best exposure settings.
This has different names from different manufacturers and software. But they both do the same thing.
When it comes to Canon metering modes vs Nikon, there is no difference in the way the scene is evaluated.
Partial Metering Mode
This metering mode collects data from a small circular area in the center of the frame. It covers about 10-15% of the entire scene.
This is useful when your subject is in the center of the frame and you want them to take priority in the exposure calculation.
There’s not a lot of difference between evaluative and partial metering modes.
It all comes down to the conditions you’re shooting in.
Spot Metering Modes
This is like partial metering only the dot in the center is smaller, roughly 5% of the frame.
You can use this for smaller subjects. I use it over partial because I know that any amount of light surrounding the subject won’t be a problem.
This is a more advanced way of working out the good exposure for your camera. This is because it involves metering for such a small area. The rest of the scene may not be correct, leaving that up to you to work out.
Notice that the skin tones are much softer and easier to look at. While this is a good thing, it leaves the rest of the scene rather underexposed.
Be careful when using this mode; it has its uses but you don’t want to end up with all of your photos in this style.
Centre Weighted Average
This is similar to partial and spot metering, only the area where the metering takes place is much bigger.
DSLR camera manufacturers realised one thing. Most people take photographs in which the subject takes up the center of the image. There needed to be an effective metering system in digital photography for this scenario to give an accurate exposure value.
You’ll notice in the photo below that the background is quite well exposed. But this is at the expense of the skin tone being horribly overexposed and unusable.
Average Metering Mode
This works similarly to evaluative metering in photography.The meter reading looks at the light from the whole scene.
But it does so in a very unintelligent way. Not only does it not recognise what’s in the scene, it doesn’t make any changes accordingly.
If there’s a bright sun or a dark shade in a scene, this region will be treated in the same way as the rest of the photo.
This often results in over and underexposed areas in the same image.
This mode isn’t usually found on modern cameras.
Which Ones You Should Use and When
You should have a pretty good understanding of what they do and when to use them by now.
But I’d like to go into more detail about the two I use the most – Evaluative and Spot Metering.
I find evaluative to be pretty good at working out what I want in the majority of situations. For me, it would be pointless to switch to partial or centre-weighted.
The other mode I use is spot metering. This is where I find evaluative doesn’t deliver too well. This gives me more control over the scenes exposure.