Aperture is a fundamental aspect of photography. The exposure (brightness) of an image is determined by the aperture, shutter speed, and ISO (referred to collectively as the “exposure triangle”). Yet many photographers don’t fully understand aperture, and when to choose which f-stop. It’s more than just a setting—it’s a creative tool that can dramatically impact the look and feel of your images. Understanding how aperture affects depth-of-field, exposure, and sharpness will help you take control of your photography and achieve your artistic vision.
With Fujifilm cameras, you’ll typically control the aperture via a ring on the lens, which are marked in f-stops. A large aperture has a low f-stop number, such as f/2, while a small aperture has a high f-stop number, like f/16. There are full-stops (e.g. f/1.4, f/2, f/2.8, f/4, f/5.6, f/8, f/11, f/16, f/22); in-between the full stops are intermediate stops, which are most commonly third-stops (e.g. (f/1.8, f/2.2, f/2.5, f/3.2, f/3.5, f/4.5, f/5, etc., etc.) and less commonly half-stops (e.g. f/1.7, f/2.4, f/3.3, f/4.8, etc.). A large aperture (low f-stop number, such as f/1.4 or f/2.8) allows more light into the camera and also creates a shallow depth-of-field (only a narrow slice in focus), making the subject stand out against a blurred background and/or foreground—common for portraits, where you want to separate the subject from distractions. A small aperture (high f-stop number, such as f/11 or f/16) allows less light into the camera and also creates a large depth-of-field (lots in focus), which is common for landscapes where you have several compositional elements at various distances from the camera.
The closer the subject is to the end of the lens, the more shallow the depth-of-field will be, and the further the subject is, the larger the depth-of-field will be, regardless of the aperture. In other words, the focus distance and aperture work together to create the depth-of-field, whether narrow or expansive. To achieve a narrow slice that is in focus (a small depth-of-field), one should position the subject close to the camera and use a large aperture (for example, f/2); to achieve a broad slice that is in focus (a large depth-of-field), one should position the subject further from the camera and use a small aperture (for example, f/11).
The aperture you choose determines how much light enters the camera (shutter speed determines for how long the sensor will be exposed to that light). A large aperture (such as f/1.7 or f/2) allows more light to enter, which is useful in low-light conditions, such as indoors or at night. A small aperture (such as f/13 or f/16) reduces the amount of light, which is useful in bright daylight situations. Even though you might wish for a shallow or large depth-of-field, the conditions might prevent you from using the most ideal aperture for what you want to achieve.
Adjusting the aperture affects other exposure settings. If you open up the aperture for more light, you may need a faster shutter speed and/or a lower ISO to compensate. Conversely, if you stop down the aperture, which allows less light, you might need to increase the ISO or use a slower shutter speed. This is a balancing act that should be thoughtfully considered—compromises are often necessary.
Aperture also influences sharpness. While stopping down (using a smaller aperture) generally increases the area of sharpness (depth-of-field), it might actually decrease sharpness. Every lens has a “sweet spot”—an aperture range where it delivers the best overall sharpness. For many lenses, this is between f/4 and f/8 (this is generally speaking, and varies from lens-to-lens, and even sensor-to-sensor). At large apertures (such as f/1.4), lenses can exhibit softness around the edges due to optical imperfections, and also decreased overall sharpness. At small apertures (such as f/16), diffraction can reduce overall image sharpness. Selecting the optimal aperture range for your lens will ensure the sharpest photographs.
F-stop is more than just a technical setting, it’s an artistic choice. Large apertures can create dreamy backgrounds and subject isolation, small apertures ensure everything is in focus, while the middle apertures produce sharply detailed pictures. Whether you’re shooting portraits, landscapes, street photography, still-life, macro, or any other genre, the aperture choice will significantly effect the outcome, giving you creative control over your photography. Experimenting with different apertures will deepen your understanding of how they impact your pictures—the more you practice, the more intuitive it will become. The next time that you’re out with your camera, take a moment to consider the f-stop, because it’s one of the most powerful tools at your disposal.
This post contains affiliate links, and if you make a purchase using my links I’ll be compensated a small amount for it.
Fujifilm GFX100S II:
Amazon, B&H, Wex
Fujinon GF 80mm f/1.7:
Amazon, B&H, Wex
Fujifilm X-T5 in black:
Amazon, B&H, Moment, Wex, Nuzira
Fujifilm X-T5 in silver:
Amazon, B&H, Moment, Wex, Nuzira
Fujinon 56mm f/1.2 R WR:
Amazon, B&H, Wex, Nuzira