I chose to explain aperture last because it is the last photography concept of the bunch that I came to understand. I’m not sure why it was so hard for me, but I went for months only shooting on shutter speed priority because I just couldn’t understand what aperture was or how to use it. Then one day everything kind of clicked for me! Hopefully reading this post will help you have that “A-ha!” moment as well.
What is aperture?
You’re going to have to work hard to stay with me on this one because there are several different terms I’m going to have to use to explain this concept. Just like the other concepts, aperture has to do with light (photography is all about light if you haven’t realized it by now). First I’ll show you the part of your camera that is affected when you change the aperture.
Ignore the numbers for a second, we will come back to those.
See that little circular thing? It’s called a diaphragm. The width of that opening determines your aperture. Except it all gets very confusing because a BIGGER opening means a SMALLER aperture number. This is what kept me so confused for so long. I just couldn’t remember the bigger/smaller thing. If you keep reading I’ll teach you the phrase that helped me remember how it works.
Aperture, like everything else, is all about light. Having the opening very small lets in less light. Having it very big let’s in lots of light. Now look at the picture above again. See the numbers? Those are the measurements of the aperture, and they are called F-STOPS, and when photographers are abrreviating the F-STOP in writing, they write it out like f/8.0 (say that out loud using the phrase “f-stop of eight”). If I start with f/1.4 and then change to f/2.8 I have gone up by two stops.
So when a photgorapher tells you they take their picture on f/1.4, they are telling you that they took the picture with the diaphragm wide open to let lot’s of light in. Jasmine Starr, one of my favorite photographers, has said many times that she shoots “wide open”, and she is saying that she likes to shoot somewhere around f/1.4.
So do you understand what aperture is now? It’s the size of the opening of the diaphragm.
What does aperture do for my pictures?
Aperture affects the depth of field. Depth of field, is quite simply, the portion of a scene that appears sharp in an image.
The photo on the left illustrates a very shallow depth of field. She is holding the bouquet next to her body, but only the flowers are in focus. A photo with all parts in focus has a very large depth of field.
I wanted to show you how changing the f-stop changes the depth of field, and so I attached the Canon 50mm f/1.4 lens to my camera, which opens up all the way to f/1.4. I started out by arranging the dog and the fire truck so that they were going to be varying distances away from me. If they were all lined up in the same “field” or plane together, I would be able to have no depth of field. Does that make sense? You will see in a second.
I started out with a very small aperture. f/22
An aperture of f/22 has a very great depth of field, so all the things in my photo are in focus.
As you scroll down through these images, pay attention to the face of the man in the fire truck. You’ll be able to see less and less detail, and eventually the eyes disappear completely.
Then I stopped down all the way to f/4.0. This photo has a shallower depth of field than the ones above.
Next I stopped down as far as my lens would go, to f/1.4. See how only the very front of the dog is in focus?
Now I’ll teach you the trick that helped me to remember how aperture works.
A smaller number will have less in focus.
Isn’t that super easy to remember? So when you are out taking picture of a squirrel, and you want just the squirrel to be in focus you can think “I should take my aperture number down to f/2.8 so that I can have just the squirrel in focus and not the entire tree he is sitting in!”
Smaller number = less in focus. You’ve got it, right?
Here is a side by side comparison of the difference between f/22 and f/1.4. The photo on the right illustrates why I like shooting very wide open, with small aperture numbers, because it makes the out-of-focus items in the photo so creamy.
Shooting with an aperture of f/1.4 can be tricky though, because the depth of field (DOF) becomes a little sliver.
In this photo, the focus is on his ear, and his nose is out of focus.
In this one, I focused on his nose, and now his ear is out of focus. When you’re shooting a close-up portrait of someone, f/1.4 is usually too wide. I like to stick with something closer to f/2.2 for most of my work.
Though I like to shoot with a very wide aperture (small number) quite often, there are times when a larger number is necessary. When I’m doing group portraits at a wedding, I have to remind myself to move my aperture to something closer to f/8.0 to make sure that both the bride in the front of the picture, and her 6th-cousin-twice-removed four rows back are both within the DOF for that setting. Otherwise that cousin of hers, the one she hasn’t seen in 10 years, will be blurry!
To be clear, aperture is not depth of field, it merely affects what the depth of field is in a photo.
Aperture, out of all of these concepts, is the one where you most need a dSLR to manipulate it. I took these photos with a lens that has an aperture range of f/1.4-f/22, which is something that a point and shoot just can’t have.
I hope that this series of very basic explanations has helped inspire you to start expirementing with your photos a little bit more. I encourage you to practice, practice, practice, because that is how I came to understand them like I do. I spent so many hours on my tummy taking still photos of food and other objects around the house for my blog posts, and over time I began to better understand how ISO, Aperture, and Shutter Speed work together to create beautiful, well-lit photographs.
I reccomend starting with still life shots in the same lighting conditions. Learn how to take pictures of things using the three concepts (ISO, Aperture, Shutter Speed) all in the same light. Then move to a different lighting condidion and practice there. Over time you will slowly be able to jump from place to place, taking picture with varying shutter speeds, ISO settings, and different depths of field.
Then the day will come that you find yourself shooting exclusively on manual because you like having the power to take the photographs you want to take, not what the camera tells you to take. It’s a wonderful feeling!