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.
Part 2: Shutter Speed, Part 3: ISO
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You do a good job explaining the technical aspects of shooting, Ritchie. It’s valuable to know, as most people probably just let the camera choose. 🙂
Thanks, I appreciate the kind feedback!
Good tutorial on aperture and its effect.
One more word on the ‘Exposure Triangle’ (aperture, shutter speed and ISO). These are the most important parameters for creating technically perfect photos. But nowadays a change is taking place. To not only perfect photos, but to perfect photos with a creative look. You should therefore speak of an ‘Exposure Pentangle’ by adding two positions to the triangle:
The position of the light (backlight, side light, direct illumination …) and the color(grading). And this is where Fujifilm comes in with its film simulations of unmatched quality. And of course your brilliant website.
Professional photographers have always created their own individual look, be it in the darkroom in the past or later in digital post-processing. And with Fujifilm cameras I can do this directly, without lengthy computer sessions. And I can judge the result live, i.e. on site.
Very interesting. I had never thought of it quite like this, but it makes a lot of sense. There’s certainly more to the story than just a “technically correct” photo with the “right” aperture, shutter, and ISO combination. Maybe I’ll have to add a couple more parts to this series…. I appreciate your kind feedback!
I tend to think if an Exposure Pyramid: I think the final desired brightness is an important factor. Or considering that most meters work with distance from the “ideal” exposure, the exposure compensation.
If relying on a camera’s meter at all, I think it’s a pretty important consideration. A camera will often attempt to meter a shot like balloons at night the same way it would meter desert dunes at noon, and they really shouldn’t be treated the same way. We’ll typically prefer the balloons to be a darker overall scene, so that it feels like night. If I’m out shooting at night, I’ll use -2 EV or so, so that the camera can find the ISO or shutter speed that leaves things a little dark, and lets the bright highlights pop
While any three points between Aperture, Shutter, ISO, +/-EV will determine the fourth, given the lighting conditions, I personally find it easier to think in EV than ISO. I don’t look at a scene and think, “I need 1600 ISO for this, or 400 ISO” but I can look and think “I want this to be a bit brighter, or a bit darker.” The thing I know about ISO is that I want it as low as possible to get the rest of my settings close to where I want them.
We’ll get to ISO soon, but for me, when I switched to digital, it took a big mind shift, because with film, it was a pre-choice that was fixed. I chose the ISO in advance, perhaps before even realizing the exact light, or sometimes because that was the film already in the camera. It was set, and the aperture and shutter were the only adjustable values. While exposure was a “triangle” or “pyramid”, for practical purposes, it was just two parameters to think about: aperture and shutter. With digital, it’s a completely different story, and ISO plays a larger and more complex role, I think. Thanks for the input!