Guest post by Justin McKee
Aperture. It’s a funny word and it’s a photographic feature that photographers worldwide love to utilize to create artistic and aesthetically appealing images.
So what is it exactly?
A camera’s aperture is entirely inside the lens of the camera. Aperture is the opening through which light travels through a lens and, depending on how large that opening is, aperture can control how much of a photograph is in focus. The opening is created by small blades that convene together to control the size of the opening. If you ever use a pinhole camera, the pinhole is that camera’s aperture.
The numerics involved in controlling aperture are called F-stops. The “F” stands for “focal ratio.” On a camera you’ll see apertures labeled as f/2 through f/32 (or higher, depending on the lens). We’ll discuss the numbers later on — they can be a little confusing at first glance.
Before going into the focus aspect of aperture, let’s discuss how aperture affects the exposure of a photograph. We just learned about shutter speed and how a faster shutter speed can create a darker photo — similarly, aperture can control how bright or dark a photograph turns out.
An aperture that is wide open (as wide as the opening can be) will let more light into your camera. It’s a larger opening, therefore more light can travel through the lens. Alternatively, an aperture that is smaller will let in less light. There are pros and cons to having a wide open aperture as well as a smaller aperture.
WIDE OPEN APERTURE
A wide open aperture lets in more light, which is great for shooting in low light conditions. Using a larger aperture is ideal for indoor shooting and in dark places because more light is allowed to hit the camera’s sensor.
When you shoot with an aperture that is wide open, a few things can happen to your photograph. If you have a foreground subject that is far away from your background, the background will be significantly out of focus. This is great for minimalistic photography, macro photography and is especially appealing to portrait photographers. Having a wide open aperture creates a lot of visual interest in the photograph because only your subject is in focus. The viewer of the photograph is forced to look at the main subject because it’s the sharpest feature of the photograph.
Having a wide open aperture can be a bad thing in some instances. In fast-paced photography like sports, where your subject is constantly moving, you may find a lot of your photos quickly become out of focus because the depth of field, the area in the photograph that is in focus, is much smaller. The best way to see depth of field is if you set your camera’s aperture to as wide as it will go and focus on a subject. Step forward and you’ll notice that the subject will really quickly become blurry. Step backward and the same thing will happen. With a wide open aperture, there’s only a very small plane of focus.
Additionally — and this depends on your artistic preference, a wide open aperture also can introduce something called vignetting into a photograph. Vignetting is where the corners and edges of a photograph become darker than the rest of the photograph. Some people really like vignetting, some don’t. It really depends on what you’re shooting too, so keep that in mind when deciding what aperture to use.
A wide open aperture’s numeric on the camera, depending on the capabilities of your lens, is generally around f/2 through f/4 or f/5.6. The number following the “F” is the measurement of the diameter of the opening in millimeters.
Using a smaller aperture is more ideal when it’s really bright outside or if you’re using a tripod and can use a slower shutter speed to make up the difference. A smaller aperture creates a much larger depth of field and can allow more of your photograph to be in focus.
Ansel Adams, the photographer famous for his images of Yosemite National Park, loved using an aperture that was small because it allowed for maximum sharpness in a photograph. The smaller aperture also limited vignetting in his photographs. Vignetting isn’t always ideal for landscape photography.
In a scenario similar to before, if you set your aperture to a higher number such as f/16 or f/22 and focus on your subject, when you move backward or forward your subject will stay in focus a lot longer than if your aperture was at f/2.
A good example would be: If you’re a product photographer and can control how much light is in your photograph by using lamps, having a smaller aperture can really help make the object you’re photographing be completely in focus. The lamps bring in additional light, which helps make up for using the smaller aperture.
The odd thing about the numerics involved in controlling aperture is that the smaller the number, the larger the opening. The larger the number is, the smaller the aperture is. It’s the only number in photography that is backwards. Fun, eh?
Consider your aperture carefully when shooting. It can be a great tool to make your photographs really shine.
Next post we’ll dive head first into the last photographic feature that can control how an image turns out. We’ve already discussed it a little bit throughout the past few posts. Controlling a camera’s sensor sensitivity is vital to create good images; it’s called ISO.
Justin McKee is a small-town photographer with big ideas living in Michigan. In addition to portraits, wedding photography and video, he also enjoys wildlife photography. He always seeks to learn more about his craft.