Understanding the exposure triangle requires you to have a firm understanding on aperture, shutter speed and ISO. These three settings make up the exposure triangle. Each setting is extremely important to create a properly exposed, sharped photo. The key is making sure you understand how to get them to work together to create the photo you want.
What Is Aperture?
Aperture is the hole or opening in which light travels through. It determines not only how much light to bring in, but also how much of your image is in focus.
If you want to bring in more light to your photo you will want to shoot with a smaller aperture number which is often referred to as “opening up your aperture”.
The diagram below illustrates that.
To decrease the amount of light coming into your image you will use a higher aperture setting. This is referred to as “closing your aperture”.
Besides affecting the light in your photo aperture also plays a large roll in how sharp your image will be.
If you have ever looked at a photo where the subject is tack sharp but the background is blurry, this is created by their choice of aperture.
The smaller the aperture number then less of the photo will be in focus. That means you will have that nice blurry background.
The larger the aperture number then more of the photo will be in focus.
Shooting “Wide Open”
Another thing to keep in mind about when people talk about aperture or f stops is they say they their aperture is “wide open” or a “narrow” or “smaller aperture”. When people say they are wide open or to “open up your aperture” they mean to lower your number. For example, if you are shooting at f3.5 and you open up your aperture you would change it to maybe f2.8 and if you want to shoot wide open you would change it to the lowest number possible depending on your lens.
Creating Blurry Backgrounds
The thing I love most about setting my aperture is creating those blurry backgrounds that look so professional :O) Plus, if you are shooting in your house and have your aperture wide open it helps to hide the mess that may be in the background :O) That is one of my favorite tricks :O) Here are a few examples of what a picture will look like using different aperture settings. Notice how in the ones where my aperture was wider there is some great bokeh and as my aperture was more closed up you can see all the details in the background.
Here is another example for you (you know how much I love picture examples :O)
Did you notice in the first one there is a huge tree that is coming out of her head?? Nope! Thank you aperture!!
As if you didn’t have enough examples of the blurry backgrounds, I wanted to show you another example but with flowers :O)
Thanks to my friend, Trisha, for being such a great model :O)