Metering Modes

That’s right. The word “mode” again. And the most important way to adjust our camera to get the right exposure, after exposure compensation.

First, A bunch of Icons

meteringmodeicons.png

Right, this very advanced drawing that took me a lot of time to make is all of the icons for most of the different metering modes on most cameras.

Metering Modes?

First, make sure you’ve read the section on the histogram. Remember how we consider a ‘correct’ exposure was where the pixel’s brightness values had nothing over or under exposed, and thus largely were clumped in the middle of the histogram?

The metering mode changes what section of the image the camera is measuring. We spoke about histograms at looking at the entire grid of pixels of an image, which it does. Yet, we don’t often really care about the entire grid of pixels of an image.

Changing the metering mode changes how the camera measures the brightness of what it can see.

We call it’s measuring capabilities the ‘meter’. There are separate devices called light meters that measure brightness. Our cameras have a light meter built right into them. we just call it the ‘meter’ since ‘light meter’ is redundant, obviously we’re talking about light, it’s a camera.

First, lets consider a standard metering mode available on almost all cameras (even film cameras!). Center-Weighted metering.

Center Weighted Metering

In center-weighted metering, the camera doesn’t care if the pixels at the edges of the frame are over or under exposed.

Let’s say we have this image of a house and a cat on a sunny day.

sunnyday

Center weighted metering would look at all of the pixels that are red (in the following image) and try to get just those pixels to be middle-grey - in the middle of the histogram.

sunnyday_center

Notice how some of the red pixels are transparent. It’s looking at images between the center and the edges, and trying to get them to be middle-grey, but not as much as the ones in the center. Thus the term center-weighted.

Consider our first image, If we adjusted the brightness so the entire image averaged as middle-grey as possible, it would look like the left half of this photo:

sunnyday_autoadjusted.jpg

The sky is so bright that the camera would have to get a darker exposure, and in the process, it would darken the foreground (the cat, the ground, etc) much more than we want.

In real life, such an effect looks like this:

tom_under

Sure, our sunset has color… but Tom, a photographer I met on this beach in Naples, is totally underexposed!

Center-Weighted metering could help prevent this. Enough of the ocean and Tom’s face would be considered, and the bright sky would be more ignored.

Spot Metering

What other types of metering are there? The next most important one is spot metering. Spot metering doesn’t take much of an average, but looks at a really small section of the image. This spot is usually right the center or on the currently selected autofocus point. We measure just that spot, and try to make that a middle-grey, correctly exposed, brightness.

sunnyday_spot

The red dot is at the top left of the house

The size of this spot depends on the camera. Nicer cameras tend to have smaller (more accurate) spots.

The secret to spot metering is not hoping that that the center of our image happens to be a middle-grey) tone to base the exposure of the image off of. Instead, we point the spot at exactly the point we want to to be correctly exposed, measuring it, then recomposing and taking the photo, exposed correctly.

Look for something in the scene that is middle grey, point the spot at it, and measure that. Some videoographers use ‘grey cards’, pieces of paper that are the exact right grey tone, that they can put in their scene, under their lights, and get a perfect measurement. We don’t do that, we juts look for something greyish.

When we measure a spot, we may not be pointing the camera in the right direction, how do we ‘lock’ that exposure we measure in, and recompose our scene?

Camera’s all handle that measuring process differently. With Nikon, there is an AE-L (autoexposure-lock) button to press, canon that same button looks like a star, some cameras lock the exposure when they lock focus (camera button held halfway), and this behavior can - of course - change depending on the settings of your camera. The quick answer is to find your specific camera’s manual or guide and read it (try a google search first), this behavior is just a bit too different for each camera for me to cover here.

One more note about spot-metering. One can combine it with exposure compensation for a really powerful workflow. For example, I know that I want a grey sidewalk in the shade to be a few stops darker than middle grey, and then I will have a good exposure. I meter the sidewalk, and use exposure compensation to go minus one or two stops. Perfect.

Spot metering and exposure compensation used to be how I shot _all the time. _I still do most of my street photography using this workflow. I really like the control.

I point my meter at what, in my scene, I know what tone I want. Maybe I point it at a cloud and tell the camera to overexpose - if that cloud is important. Maybe I point it at my cat’s darker fur and tell my camera to underexpose. I like this way of shooting because I know what matters to the photo - the detail in the cats fur, the fluffiness of a cloud - is going to be captured how I want it to be.

Shooting like this, metering spots then exposure compensating those spots to be the brightness you want them to be is very powerful. I highly recommend everybody try it. If nothing else, it will help one learn how to identify brightness in a colorful scene. IE: how to see the world in black and white.

Partial Metering

Sometimes, a spot is too small to get an accurate or consistent exposure. Maybe measuring the grey t-shirt of somebody left you measuring the white text on the shirt, by chance.

Canon introduced partial metering to handle these cases. It’s basically spot metering with a slightly larger spot, and more ‘falloff’ (the red dot would be a smoother gradient).

I like partial metering a lot because I can shoot pretty lazily and don’t want to spend too much time thinking of exactly where the spot should go, yet I still like to measure and recompose as a shooting method.

Matrix / Evalutive / Multi / ESP / Honeycomb / Auto

The last metering mode that most cameras have goes by a million different names. I am going the to call it “smart” metering. Smart metering is when the camera doesn’t just try to reach grey at one average of the image, but looks at different sections of the image, takes a guess as to what is more important, and then tries to get that to be exposed correctly. In other words, it tries to guess what you are taking a photo of based on what information it has - brightness levels of different places in the frame - and expose for that.

This way, one super bright point doesn’t throw off an average. If the camera see’s a bunch of brightness towards the top and darkness towards the bottom, that’s probably the sky and the ground; it will look for other parts of the image to meter off of, and not expose for the sky (remember Tom, above?).

It works by looking at the exposure of different areas on the image that it is taking a photo of, comparing it to a database of exposures for similarly measured images, and choosing the appropriate exposure. In other words: total magic AKA awesome engineering.

Nowadays cameras consider a whole bunch of other information, including the focus distance (what is in focus matters more), the depth of field of the current settings, and way, way more.

It all started when Nikon introduced their matrix metering mode on the Nikon FA. It was so much better than what came before it that most of the time a photographer finally didn’t really need to worry about the exposure.

If you want a good read about the development of this technology, take it from Nikon themselves. (Seriously, it’s a good read).

Wow! It’s super awesome technology that has had an amazing amount of time and energy invested into improving it.

…Yet, it still sucks sometimes.

First, smart metering modes tend to value the auto-focus point too much (IMHO). This makes it worse when using manual focus and/or worse when you focus on something you don’t want to be middle-grey, like a silhouette.

Second, it biases towards it’s own ideas of a ‘correct’ exposure that makes good images “straight out of camera”. Often, we want to over or under expose different parts of our images in order to ensure that these parts have more ‘data’. More contrast coming out of the camera that we can play with while editing. Smart metering modes do not necessarily give us the best image that we can edit with later, it tends to assume you won’t be editing at all.

Finally, it can be inconsistent between two similar shots. In fact, barely moving the camera may accidentally produce two differently exposed images, which makes editing and reviewing the images a pain. This also makes cameras less pleasant to use, as there is nothing a photographer hates more in a camera than unpredictability.

“Photographers these days are too spoiled on their cameras. All their photos look the same!”
This quote is from my grandfather, best I can remember it. He did shoot with a hasselblad medium format camera and almost always used manual controls. He once duct-taped a film camera to the front of his skii’s and jumped out of a helicopter and skii’d down a mountain back in the 60’s. Take that, GoPro!

He is remarking that auto-modes don’t just just some of the hard/monotonous parts of photography and make them easier. They also take over elements that are a crucial part of the creative photographers toolkit. Don’t let your camera get in the way of taking an interesting image!

Manual Exposure

When shooting in manual, most camera’s still go through the effort of metering the scene. The measured output is still visible on the exposure compensation meter (the actual number line on the camera screen), and one can use it as a starting point or reference when dialing in an exposure.

Videos On Metering Modes