Introduction To Using Manual Mode: The “Exposure Triangle”

The Exposure Triangle. Ever wondered what that photography buzzword is all about? I know that I sure did and I had no idea where to start when I first came across it. But looking back on my experience… this is where I would have begun:

Exposure: how light or dark your image is. If the image is too light then it is “overexposed” if it is too dark it is “underexposed”.

The Exposure Triangle consists of three parts 

  • Shutter Speed
  • ISO
  • Aperture

To begin the journey through them we will start out with shutter speed, because it is the simplest to get a good grasp on.

Shutter Speed

Unlike many things in life such as “fun sized” candy bars and sugar free baked goods, shutter speed is exactly as it seems. It is literally the speed of the shutter. The shutter is like our eye lids. If it is open, light comes in, if not, light doesn’t. Simple as that.

Whether or not you shoot Canon or Nikon, it is the number that is down in the bottom left of your viewfinder. It will appear as a number like 200 or 640 or 1000 or 50(or many other whole numbers). In reality, it is a fraction. So 200 is 1/200, or one two hundredth of a second. 

Allowing the shutter to be open for a long time will brighten the exposure.  The less time that it is open, the darker the exposure will be. 

The second part of shutter speed is motion blur. If you keep the shutter open for a long time it will let a lot of light onto your camera’s sensor. However, while it is open it will also still be recording light information from your subject, and if it is moving, it will be blurry. It is much like in cartoon animation. When a character is moving fast they are often shown as a blur. But the same thing can happen if you are snapping a photo of a child playing, and in that case it’s not so good.

This just means that you need to take into account how fast your subject is moving and the effect you are going for in the photo. If you want to “freeze”:


your subject in space and time use a high shutter speed. The shutter speed in this photo was at 4000 in order to capture this helicopter with the blades frozen.

There is also a guideline for setting your shutter speed if you don’t know where to begin:

Use a shutter speed value that is equal to your focal length.

For example, If my lens is a 50mm lens, then my shutter speed should be at minimum 1/50 of a second. Yes, you can go lower or higher, but this is a good starting place.

Now to the next vertex of our triangle! -ISO


This one was the most difficult at first for me, but then with a little practice, it became the easier to understand. Before the little details about ISO and what it does, let’s go back in time a few years to this:


This is a film camera(my roommates actually). I do not shoot film, however if you talk to someone who does, they will tell you how they change ISO. By changing the film they use.In the photo above there is some 400 film. For your digital camera, it will say ISO:400. With film camera’s you had to change film to adjust ISO, but with digital, you can adjust it when you like… to what you like. 

For simplicity, ISO can be explained as your film’s sensitivity to light, or the sensitivity of your digital camera’s sensor to light. The higher the ISO number, the more sensitive to light, and the brighter the image. 

The trade-off to having a more sensitive sensor or film is grain. You may also hear the “grain” called “noise” as well. These terms can be used interchangeably.

 Take a look at these two photos. The only adjustments made were between shutter speed and ISO. ISO in the first image was at 100 and in the second image it was at 6400:


Doing a grain comparison with a 5d MkII is kind of silly but it is there! Let’s crop in and take a look at the difference:


See the grain now? The first image looks incredibly smooth when compared with the second image. 

That’s all for ISO! Now onto the third and final point of our triangle-Aperture.


This one is a bit more tricky, and I definitely didn’t have the first clue about what aperture really was when I started out. Just so there is some sort of frame of reference for this word we can go to the dictionary.

Webster says:

Aperture-a hole or small opening in something.

And this is just what it is. This part of the Exposure Triangle is physically located in your lens, and not inside your camera. This “small opening” is what is letting the light into your camera to hit your camera’s sensor. It can either be opened up :


Or it can be closed down:


The first image as taken at f2.2, and the second at f22. Or an aperture of 2.2 and 22.

You may have heard someone say, “I always shoot with this lens wide open.” Well the first picture is what they are talking about. As you can imagine, when the lens is “wide open” it lets in more light than it does in the second photo.

So this means can we all run around shooting at our lowest aperture?

Well we could, but as with every other part of the Exposure Triangle, there’s another side to aperture as well. That other side is the depth of field in your image. I may go into depth of field in more detail in a post of its own, but for now I will keep things simple.

A low aperture number gives you more light, and a shallow depth of field. 

Example: f1.8, f1.2, f2.8

A high aperture number gives you less light, and a wide depth of field.

Example: f22, f10, f32

This is an example of a low aperture number, and a shallow depth of field. Notice how Britanee and Bethanee(gotta love the way they spell their names right?) are in focus, and the background is blurry.

IMG_0588 copy.jpg

 This was taken at f2.8.

Now for the opposite:

IMG_8520 copy.jpg

For this I made sure to use a larger aperture number so that I could get all of the icicles in the image. This was taken at f8.

And that is all there is to it! Shutter Speed, ISO, and Aperture.  Now that all of the information we need to know for the Exposure Triangle is out there, in the next post I will go over how adjusting these 3 work in real life situations. If you thought this was helpful don’t forget to hit that like button on my facebook page.

 Keep on shooting!