Photography Basics: Aperture

Welcome to another photography basics post! This week we’re continuing the exposure theme and talking about aperture. Your shutter speed, ISO, and aperture settings work together to form the foundation of an image by controlling how much light reaches the sensor of your camera, as well as how it happens.

Aperture is probably my favorite element of the exposure triangle because it allows you to add depth to your photos. Here’s how it works. If you imagine that your camera’s lens is its eye, the aperture is the pupil. It dilates or contracts to allow light to reach the retina or, in the camera’s case, the sensor. A wider aperture, like a wider pupil, allows more light to pass through to the sensor while a narrow aperture keeps some light out.

I might come back and replace this one later…

Different lenses will have different aperture ranges available to them, so keep that in mind when you’re shooting; you might end up needing to move around a bit or even switch lenses to get the best possible photo.

I think the most confusing part to aperture is how it is measured. Aperture is expressed in f-stops; the higher the f-number, the smaller the opening. So an aperture of f/16 is a fairly small opening, while f/1.4 is very large. There is a reason behind this, but it’s…a lot of math. I plan to go over all of the math behind exposure stops in a later post, after we’ve finished going over all three of the basic elements, but I thought I’d leave it out today for simplicity’s sake. I’m not sure how many of you are interested in the mathematical and technical side of photography, and how many of you are more interested in the creative side, but I’ll hazard a guess that it’s mostly the latter. So let’s keep going.

The biggest creative aspect to controlling your aperture is having control over your depth of field. This will allow you to take sweeping landscape shots with every part of the image is in razor sharp focus or, if you’d rather, you can take portraits with soft blurs or bokeh behind your subject. You have to be mindful of your depth of field when you’re composing a shot and selecting your aperture setting, otherwise your subject may end up a little out of focus.

Notice how the sunflower in front is in focus and the other is not? Oops. My aperture should have been a little smaller to get both flowers looking sharp.

When I’m shooting a subject that is not in motion, I try to determine my aperture first so I know what part of the image needs to be in focus, and then use shutter speed and ISO to compensate for the amount of light that comes through the lens opening. Most DSLRs have an aperture priority mode, which helps you to keep your exposure balanced while giving you control over your depth of field, but I prefer shooting in manual and having full control over my camera.

When taking landscape photos, you generally want to have a small aperture so the entire scene is in focus. I haven’t done a lot of landscape photography at this point, but I do have a few examples to share with you.

Mead’s Quarry

Here’s a shot from my walk around Mead’s Quarry the other day. A small aperture (f/10) allowed me to take full advantage of the morning sun and beautiful landscape. I probably could have gone a little smaller and gotten an even better shot, but I think this is pretty good. I love the reflection of the rocks in the water.

Knoxville taken from Sharp’s Ridge. It’s a shame about the power lines because this is a magnificent view.

This shot is from Sharp’s Ridge. Once again, I used a small aperture (f/16) to really take in the scenery. If it had been a clear day, we would have gotten a really great view of the mountains in the distance, but I think this is still pretty good.

Now let’s look at some of the benefits of using a large aperture.

In my experience, a large aperture is better for portraits or for shots where you want to have a dramatic blurred background or foreground. Have a look at some of these to see what I mean.

French macarons from Honey Bee Bakery in Knoxville

See how the macaron in front is clear and the others are blurred? I shot this with f/2.5 to give it that soft look. I wish I had better lighting in my kitchen, but renters can’t be choosers I guess. (And we’re planning on moving soon anyway, so keep your fingers crossed that I find a place with good lighting). This kind of shooting is good for food bloggers who want to show off their delicious creations. It would also be an attractive way for someone to display items they’re trying to sell online.

A hibiscus on a wire bench.

This is a pretty cool one. Both the foreground and background are blurred, leaving the flower and the back of the bench in focus. The aperture for this shot was f/7.1, which is sort of a middle ground.

I hope those were good examples for you. If you have any questions, please be sure to ask in the comments below or send me a message on Facebook. I want these articles to be easy to understand and helpful for beginners who are branching out into manual mode. If it’s overwhelming for you to shoot strictly in manual like I do, try experimenting with aperture priority if that’s a feature your camera offers.

Remember, you can also use your ISO and shutter speed to control how much light is in an image. These three elements play off of each other, and figuring out the best way to balance them takes some practice. Don’t be discouraged if your first foray into manual mode doesn’t give you perfect results; just keep trying until you get it right. Next week, we’ll cover the last element of exposure, ISO. In the meantime, please be sure to comment and share!