Exposure Settings - What Are They & How Do They Work?

The Exposure Triangle

What is the Exposure Triangle?

When you are starting out with your camera, digital photography it can be a bit overwhelming to deal with all those various available settings. The first thing and I'd even say the most vital step is to learn about is the exposure triangle. Sounds about as mysterious as the Bermuda Triangle doesn't it? Actually it really is reasonably simple - it is the relationship between your shutter speed, your aperture and your ISO settings. Those 3 work together to create a photograph. Exposure is best described as the amount of light that hits your sensor for a particular duration of time. 

The exact same principle applied when everyone shot with film cameras - except that the light was exposing on actual film. That's how I started out in high school, shooting with a film camera and then developing the pictures in a darkroom. The challenge with that was twofold - you had to have your exposure settings exactly right, and you had to choose the correct ISO film for the conditions and scenes you were capturing. The digital camera sensor now acts as our "film" and it's a huge advantage! Now we can play with all our exposure settings and see the results immediately, then adjust those settings as necessary. 

 The reason we call it the exposure triangle isn't really all that mysterious either - it's  because when you adjust one of the 3 exposure settings, another of the 3 settings must also change to get the very same exposure. Learning this relationship between shutter speed, aperture and ISO will be a very important foundation as you learn and practice your digital photography. So let's review the basics of each of them. 


What is Aperture? 

This is most simply described as the ‘the opening in the lens.' When you hit the shutter release button of your camera a hole opens up that allows your cameras image sensor to catch a glimpse of the scene you’re capturing. The aperture you set impacts the size of that hole. The larger the hole the more light that gets in – the smaller the hole the less light. 

So it controls brightness but it also controls depth of field.  That is the range of distance that determines what will appear sharp in your photograph. When the background of your image is blurry, you have shallow depth of field. This is because the point you are focusing on that is in focus is very small. Typically, the larger the hole (larger aperture) the more blur effect you will get  If you take a picture of a landscape and the whole thing is in focus from front to back, that is called a deep depth of field and your aperture setting would be a smaller hole. A large area of the image is sharp and in focus. Different lens models have different aperture capabilities but you always control your final aperture from the camera setting. 

What is Shutter Speed? 


The shutter is arguably the most basic component of any camera. When you push the shutter button you snap the picture!  It’s more or less a curtain that covers your camera’s sensor that opens to allow light in, and closes to stop it. The shutter speed setting controls how long the exposure is. Here's a couple of simple examples - we can use a short shutter speed to freeze movement or action - we can use a long shutter speed to capture movement, star or light trails, or to capture very dark scenes without having to increase the ISO or make the aperture smaller. You can actually do a lot of very creative photography with various shutter speed settings, but understanding how to adjust the other 2 elements as you capture your subject or scene is the key. 

What is ISO? 

 ISO is probably the easiest of the 3 elements to understand but it can be tricky to adjust it in concert with your other 2 triangle settings to get the correct exposure. ISO is simply how sensitive your camera sensor is to capturing light. A low ISO number means your digital camera sensor is less sensitive, and a high number means it is more sensitive. .A higher ISO makes it so that the sensor does not need to collect as much light to make a correct exposure, while lower ISO settings make it so that the sensor will have to gather more light to make the exposure. There's a lot more to it but that's the basic idea. 

How do they work together - how do I decide?   

As you reviewed the 3 exposure triangle settings you may have realized that while each of the three variables work very differently, they can all effectively produce the same result. They allow more or less light to reach the sensor. It’s really simple as that. So you may ask “why would I change one over the other?” This is the point where the technical becomes art. Each exposure variable has its own characteristic that it brings to the table. That's where continued learning and practice practice practice comes in!

We cover the 3 exposure triangle settings in our beginner workshop and we practice as we go so that you can begin to learn the relationship between shutter speed, aperture and ISO. Join us at our next beginner workshop in Regina, Saskatchewan on Sunday April 14th 12:30pm to 4:00pm at Connaught Library located at 3435 13th - Avenue. Registration is required to attend. Maximum of 12 participants. 

Book your seat HERE