Category: Operating

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

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.

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.

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:

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:

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.

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

The Histogram

Exposure Compensation

Exposure Compensation is an absolutely critical feature of the camera to understand.

Exposure Compensation is a way to brighten or darken the image being taken without adjusting any of the properties manually.

You are taking the camera’s measurments (light-metering) and saying “okay, that, but brighter” or “sure, that, but darker”.

The exposure compensation icon is universal. It looks like this:

Exposure Compensation Icon by Martin Chapman Fromm from the Noun Project

Exposure compensation doesn’t do anything in manual mode because we aren’t using the camera’s settings. This is why the exposure compensation button is also – while in manual mode – what often serves to toggle which setting your dial adjusts – shutter speed or aperture, in manual mode.

More Reading on Exposure Compensation

Videos on Exposure Compensation

Shooting Modes


The mode dial is the thing on the top of the camera that has a bunch of weird icons, and the following letters: P, A, S, and M. or P, av, Tv, and M if you’re a canon shooter.

Mode Dial on a Canon 5Dmk3

PASM is an abbreviation of 4 modes for controlling how the camera behaves.

Canon cameras have “PTVAVM”, or “MAVTVP”, either way it doesn’t roll off of the tounge as well. We will say ‘PASM’ to refer to the shooting modes.

Camera’s have two main ways to control how much light gets into a camera. Shutter Speed and Aperture.

We’ll talk about the third, ISO, later. Aperture and Shutter Speed affect not just exposure but the look of an image. ISO is not used to creatively affect the look of an image, so it isn’t as important to understand yet.

P for Program

P is the new auto mode. Now more green camera or A+ or green rectangle mode. It’s P mode for you from NOW ON. P mode handles getting the image to look right for you, but allows you to – if you want – control other settings.

Settings like focus modes, drive modes, Exposure Compensation, and more fancy-schmancy camera talk that we will get back to later.

S (or Tv) for Shutter priority

or Tv for “time-value”

This mode gives a new control for our camera, a dial (probably by the shutter button, on the top. Maybe on the back), that lets us control what the shutter speed is. How long the camera lets light in for. We’ll talk about shutter speed later. Just now that it is measured in seconds, a unit of time; and S mode gives us control over it.

Canon calls it “Tv”. Everybody Else just calls it “s”.

A (or Av) for Apeture priority

Or Av for Aperture-Value.

A stands for Aperture. This mode gives you total control over the size of the hole in the lens, and the camera adjusts everything else to get the shot right. Otherwise, it’s the same as P mode. We’ll be talking about what this means later, just know for now that A mode gives you more control.

M for Manual Mode

This mode lets us control both the aperture, and the shutter speed. Also the ISO, which We’ll get to later. Manual mode means the getting the “right” amount of light is up to us, and the camera won’t make any decisions.

This is often important when you want to shoot consistently – like when stitching images together – and the camera’s decisions can fluxuate slightly. It’s also super useful when we want to take photos that are too dark or too bright.

Later you’ll be out and about shooting in ONLY manual mode. We aren’t there yet. Relax. Everything is going to be okay.

Mode dial on a Canon 70D

Burn The Flower

No more flower (“macro”) mode. No more person-running (“sport”) mode, and no more mountain (“landscape”) mode. These are just variations of program mode that perform better in certain situations.

Sport mode, for example, shoots with a faster shutter speed so shot’s are less likely to be blurry. From now on, if you had to shoot a sporting event and didn’t want blurry shots, you’ll go into S mode and dial up the correct settings yourself.

This advanced control is important because while cameras are really really good at what they do, they’re still limited by many assumptions – the camera doesn’t know what it’s pointed at. Only you know what you are trying to capture and emphasize. It’s also important for learning how these things work!

Becoming a photographer means taking control over these decisions.

The Camera is a Calculator

Let’s go over how What The Camera Does is being changed by the different shooting modes.

So the camera measures the scene and comes to a conclusion about how much light we need. Let’s pretend this is some single unit number, (Perhaps we call this an “exposure Value) and let’s pretend that it arrives at the number 10. We need 9 light for the scene.

Let’s say the ISO gives us 3 units of exposure value, the aperture gets another 3, and the shutter speed gives us the final 3 to get to 9 imaginary units of light. These 3 elements of the camera all factor into how much light there is.

Now, in reality, these elements are probably being multiplied by each other. Like Shutter Speed x Aperture x ISO = Exposure Value. Just… shh. Relax. Relax. Everything is fine. Math is easy. This part doesn’t matter right now. What matters is that all three of these elements contribute to the exposure of the camera. Our camera, on P mode, does all of the math for us. It decides how many units of shutter speed, aperture, and ISO to combine together to get the exposure.

On program (p) mode, the camera does it all for us.

On Aperture-priority mode, (A or Av mode on the dial), we control the aperture. We say, okay. I want an f-stop of 1.8. I want an f-stop of 8. We are deciding this unit. Like a recipe, I’m going “I want this much butter no matter what” and the camera is taking the ISO and the Shutter speed (the flour and the salt?) and changing them so our equation works out, and we get the right exposure.

Shutter priority (time value) mode is the same thing, but we control the shutter speed, we lock in this one unit of our equation, and the camera controls the other units. It’s still trying to do the same thing, to get the right amount of light into the camera.

There is no ISO priority mode.

Manual mode, we control the shutter speed and the aperture and the ISO. Fun fact, is many cameras can have the ISO set to a specific number or on ‘AUTO’ on all of these modes. So we can have ISO+Aperture locked in on aperture-priority mode and the camera changes the shutter speed, or we can be in manual mode and putting in totally wrong settings with both the aperture and the shutter speed, but the images look okay because the camera is changing the ISO for us. Then we walk around like “aww yeah I’m shooting manual and I’m nailing the exposure every time” and that’s not really true, but I’m not going to take that from you. You can keep that little victory.

Why no ISO priority mode?

The first reason is because the ISO doesn’t really affect creative decisions. It doesn’t change how an image looks, other than grainyness or noisiness. The higher the ISO, the “worse” the image, but it’s otherwise the same. One always optimizes for a low ISO, and the camera will just do that for us.

So the first reason is because we don’t need one. It would be silly.

Besides, you can go to program (P) mode and still lock the ISO to a specific number on most cameras, which then is basically ISO-priority mode.

The second reason is because of film. Before digital cameras, ISO wasn’t something you could control with the camera at all. It came from what film you decided to buy, with different films rated to different ISO’s. Different films were more or less sensitive to light. You would tell the camera “Okay, I have ISO 400 film in here now” and the camera wen’t “okay” and then you uses your different shooting modes.

Digital cameras came around and we didn’t add an ISO shooting mode, we just added a control that let one change the ISO amounts, or set it to auto. Cameras still behave the same way, otherwise! Neat!

What A Camera Does

Here’s a simple question…

What Does A Camera Do?

Okay, We should probably talk about what these things actually do. Pay attention, this is important. So what do camera’s do? You know, besides take pictures.

Camera’s are measurement devices and storage devices. They use optics (reflecting light through glass) in order to capture an image, save it, and transfer it elsewhere to be used.

Thing Cameras Do Number One: Take Pictures

Camera’s take pictures. They have a button that responds to the photographer (usually) to, at that moment, capture the light that is traveling through a lens (usually) into the camera (most of the time).

So, a camera is like an eye. Eyes see. Eyes see light. Cameras see light. With me so far?

Sometime’s it’s dark out, and other time’s it’s bright. Stay with me. Lights can be on dimmer switches. Right? Right. So light varies in brightness? Of course it does, you know this. You’ve seen a day/night cycle before.

Okay. So, if there isn’t light, there isn’t a photograph. It’s just black. No light = no photo. Camera’s need light. Too much light also means no photo – our photos will just be white. Something between white and black? That’s where an image appears. Let’s recognize light as having a brightness from zero to, uh, some big number. Infinity? (INSIDE OF THE SUN!?).

Camera’s have to change their settings to match this quantity of light, or else the image will be just black, or just white. We call this “overexposed” or “underexposed”.

An “exposure” is another shorthand word for an image from a camera, it refers to the process of capturing the light.

Thing Cameras Do Number Two: Adjust

Camera’s can adjust some properties in order to “let in” more or less light into the camera. They respond to the amount of light in the world in order to get the “correct” amount of light into the camera.

They also need to get this light in focus!

What does “correct” mean? We’ll get back to that later.

Camera’s also have controls that allow the photographer to adjust their settings. These are all those dials and knobs on the outside of fancy cameras. These are super important! Photographers can be picky about how their gear works, and have been reported to fight over what arrangement of dials and knobs is the best. Canon and Nikon users constantly fight over which direction to spin their lens adjustments is best.

So we change settings because we have to get the right amount of light into the camera! How do you know how much light to get into the camera?

Thing Cameras Do Number Three: Measure

Camera’s measure the amount of light in the world. They use this information to adjust themselves – “automatic” modes. Or just to inform you of it’s measurement, and the photographer controls the adjustments themselves – “manual” modes.

So once we capture an image that has the right amount of light… What now?

Thing Cameras Do Number Four: Save Images

Cameras’s Store and Save images. Digital cameras convert the raw data from the sensor into a file format readable by computers (.jpeg), and store that image on a removable memory card so it can easily be transferred to the computer.

In addition to the image, the file also contains metadata (data about the data) like the current date and time, which is super helpful for organizing and sorting the images. JPEG’s are a universal file type – virtually every computer and printer can handle and work with these files. They have small file sizes and are fast to work with, making them an obvious popular choice for image storage.

Thing Cameras Do Number Five: Playback

Cameras have playback, which refers to the ability to look at the images you have taken on a little screen. You can also hook many camera’s up to TV’s or other screens. Most cameras let you delete and rate images, and mark an image as ‘protect’ images which won’t let you accidentally delete it.

Thing Cameras Do Number Six: View Settings

Camera’s also usually give you feedback about what they are doing! They tell you what your battery life, drive mode, shooting mode, aperture, shutter speed, focus mode, auto-exposure mode, remaining storage space, estimated remaining shots left, and more! There’s so much information! Camera’s look strange and complicated because of all this crazy stuff they are telling you.

This guide is going to break each bit of information down one at a time, so if there is something confusing on your camera – just ignore it for now. We’ll cover it soon enough.

Except for battery life. You should figure out where your battery life indicator is. Do that now. Don’t go out shooting with a dead camera! Your images can disappointing and it doesn’t matter because you had fun and learned a lot, but if you can’t even turn your camera on? Ouch. Not a good day. This is almost as important as not dropping the camera.

Let’s Review Because This Is Important

I know this is easy and I am being condescending – of course we all know what camera’s are – but I want you to really think about these aspects of cameras as separate, different, things.

We will be learning the in’s and out’s of the things cameras do at different times, so it’s important to be able to focus on each specific thing. One at a time.

Camera’s measure light, adjust settings, capture an image, and save the image. They let us view these images later, transfer them; and they let us change all sorts of settings and behaviors.

Different cameras do each of these tasks differently.

Many older cameras, for example, couldn’t measure light at all. Photographers got really good at guessing (measuring with our own eyes!) as well as using external tools, appropriatly called “light meters”. Some cameras have many settings fixed and unchangeable. Some camera’s have all mechanical knobs for everything, some cameras use a touchscreen for everything, and everything in between. But the underlying properties of all the settings, adjustments, and why to make them is the same.

In other words, we are trying to learn the underlying principles. How to use a specific camera isn’t very helpful, but by learning these principles you can use any camera.

Learning this is learning photography!