How to adjust the aperture to play with depth of field?

There is one setting that, more than any other, can transform an ordinary photo into an eye-catching image. That setting is the aperture. And its most visible effect is depth of field. This is the area of sharpness that you choose to widen or narrow depending on what you want to convey with your image.

Depth of field can sometimes intimidate beginner photographers because it seems unpredictable. In reality, it follows a very clear logic, and once you understand it, you can start using it intentionally rather than just dealing with it.

The link between aperture and depth of field

Depth of field does not depend on a single setting. Three factors come into play simultaneously, and understanding how they interact is what allows you to truly control the look of your images. Here’s how to approach them one by one, before seeing how to combine them.

How can you play with depth of field?

Three variables determine the extent of the sharp area in a photo: the aperture, the distance between the camera and the subject, and the focal length of the lens. These three parameters work together, and changing one of them will change the result even if the other two remain the same.

The aperture is the most direct lever. A large aperture such as f/2 or f/2.8 reduces the depth of field. Only a thin slice of the scene is in focus, with the rest gradually becoming blurred. A small aperture such as f/11 or f/16 extends it. The sharp area covers a greater distance in front of and behind the focus point.

The distance to the subject plays an equally important role. The closer you get to your subject, the shallower the depth of field becomes, even at the same aperture. In macro photography, for example, a few centimetres from a flower, the sharp area may be limited to a few millimetres. Move back a metre from the same subject with the same settings, and the sharp area widens significantly.

Finally, the focal length has a more subtle effect. A long focal length, typically beyond 100mm in 35mm equivalent, compresses the scene and reduces the depth of field. This is why portrait photographers often favour focal lengths between 85mm and 135mm. Optical compression naturally helps to separate the subject from the background. Conversely, a wide angle of 24mm extends the depth of field, which explains why wide-angle landscape photos remain sharp from the foreground to the horizon.

Which aperture should you choose depending on the situation and subject?

Knowing which value to choose when faced with a real scene is what really helps you progress. Here’s how to approach the most common situations with practical, actionable tips.

How do you choose the aperture?

The choice of aperture depends above all on what you want to convey with your photo. There is no universally correct value, just the one that corresponds to the effect you have in mind.

When the goal is to isolate a subject, open the aperture wide. Between f/1.8 and f/2.8, the depth of field is reduced to the point where the background becomes soft and indistinct. The viewer’s gaze is drawn directly to the subject, without being distracted by its surroundings. This is the setting you would naturally use for a portrait, a close-up of a flower, or any situation where the context around the subject is not really important.

If, on the other hand, you want to keep the entire scene in focus, close the aperture. Between f/8 and f/16, the depth of field extends enough to cover a wide range of distances. This is what we use for a landscape, architectural, or street scene photo with several elements at different distances.

For a group photo, f/8 is a good starting point. If the people are spread out in a single row, f/5.6 may be sufficient. If they are lined up in several rows at different distances, closing the aperture to f/8 or f/11 will widen the area of sharpness so that everyone is in focus.

What many people forget is that aperture does not work on its own. If you open up to f/2.8 but are ten metres away from your subject, the background will be less blurred than at f/2.8 at a distance of two metres. Similarly, at maximum zoom on a bridge camera, an aperture of f/5.6 can produce a very interesting subject/background separation thanks to the optical compression of the long focal length. Aperture is the starting point, but distance and focal length complete the setting.

The Kodak PixPro AZ425 offers several exposure modes, including aperture priority and manual mode, allowing you to freely adjust the f-stop value according to the scene. For landscape or group photos, switching to aperture priority mode and setting it to f/8 is a simple reflex that immediately improves the consistency of your images.

How do you create depth?

A photo that gives the impression of volume doesn’t come from aperture alone. It’s often a combination of small framing decisions and settings that together create the feeling that the eye can enter the image.

The first thing to work on is the layering of planes. When a photo has a sharp foreground, a well-defined subject in the middle and a background that gently blurs behind, the brain instinctively reads depth. The foreground acts as an entry point into the scene. It could be a branch crossing the bottom of the frame, grass in the foreground, or a low wall. It doesn’t matter what it is, as long as it anchors the image in real space.

Receding lines do a similar job. A road, a forest path, a row of trees, a corridor. These elements draw the eye to the background of the image. When you add a generous aperture that gradually blurs the background, the combination is very effective.

Finally, getting closer to the subject while maintaining a large aperture greatly amplifies the separation between sharpness and blur. At one metre from a face or a flower at f/2.8, the transition is sharp and the subject really stands out from its surroundings. On a flower photographed a few dozen centimetres away, the bokeh obtained is soft and uniform, without the background competing with the main subject.

How do you achieve good depth of field?

Depth of field cannot be improvised, but it can be easily anticipated with a three-step method.

For the first step, you need to choose your subject and identify what you want to highlight. A face, a flower, an architectural detail, an entire scene. This initial decision determines whether you need a shallow depth of field to isolate the subject or a large depth of field to include everything.

Next, you need to assess your shooting distance. Move closer if you want a pronounced blur and a well-isolated subject. Move further away if you want to cover more distance in the sharp area. At the same aperture, a change in distance of fifty centimetres can significantly alter the result.

Finally, remember to select the appropriate aperture. Isolated subject at close range: f/1.8 to f/2.8. Scene with several elements to highlight: f/5.6 to f/8. Landscape or architecture with extended sharpness: f/8 to f/11.

What causes this technique to fail is a lack of consistency between these three variables. Opening up to f/2.8 to achieve blur, but staying ten metres away from the subject will give disappointing results. Moving closer to fifty centimetres for a portrait, but closing down to f/11 will give an unnecessarily sharp background. The desired depth of field is achieved when all three variables work together.

Which lens and camera should you use to control depth of field?

Technique is one thing. The equipment that allows you to apply it is another. Not all cameras offer the same possibilities when it comes to playing with depth of field. Here’s how to make an informed choice.

Which lenses are best for depth of field?

Focal length influences depth of field as much as aperture, sometimes even more. It’s a parameter that many people underestimate at first, yet it radically changes the rendering of an image.

With a long focal length, planes appear closer together visually. The scene is compressed, and this compression naturally reduces the depth of field. Portrait photographers who work at 85mm, 100mm, or 135mm know this well. At these focal lengths, the background softens gently even at f/4 or f/5.6, without the need to open the aperture fully. It’s not just a question of maximum aperture; it’s the focal length itself that does the job. And the longer the focal length, the stronger the effect.

Conversely, a wide angle of 24mm or 28mm extends the sharp area over a long distance. Everything remains sharp, from the foreground to the background. This is exactly what you want for landscapes or architecture, but it makes it very difficult to isolate a subject against a blurred background.

On a bridge camera such as the Kodak PixPro AZ528, the 52x zoom reaches a focal length equivalent to 1248mm in telephoto position. At this value, the optical compression is very pronounced. Even with a 1/2.3″ sensor, the background is blurred enough to create a clear separation between the subject and its surroundings. A bird on a branch, an athlete on a field, an animal in the wild: at long focal lengths, the subject stands out clearly from its background without the available aperture being a limiting factor.

How do you calculate the aperture of a lens?

The f/ value is not an abstract number assigned at random. It comes from a very simple calculation: f/ = focal length divided by the diameter of the open diaphragm. Two physical data points, one division, and you get the number written on the lens.

Here’s an example to make it more concrete. Take a 50mm lens. If its diaphragm opens to a diameter of 25mm, you get f/2 (50 divided by 25). If you close that same aperture to 6mm in diameter, you get f/8 (50 divided by 6). The number increases as the aperture closes. That’s why f/2 lets in much more light than f/8, even though intuitively we would tend to think the opposite.

This calculation has a real practical use when comparing two lenses. A model advertised as f/2.8 maximum physically has a wider aperture than an f/5.6 model with the same focal length. In concrete terms, it captures twice as much light at maximum aperture and produces a more pronounced background blur under the same shooting conditions. These differences are immediately apparent in the images, especially indoors or at dusk.

If you want to learn more about the relationship between aperture and visual rendering, the comprehensive guide to lens aperture explains these mechanisms in detail with concrete examples and practical use cases.

Depth of field: a setting that is quick to learn and changes everything

Depth of field is one of those settings that seems complex until you try it out, but becomes obvious once you start testing it in the field. There are three variables to keep in mind. Aperture, distance to the subject, and focal length. These three levers together give you complete control over the sharpness of your images.

What really helps you progress is conscious experimentation. Photograph the same subject at different apertures, change the distance, zoom in or out. After a few sessions, the effects become predictable and you begin to anticipate them before you even press the shutter button.

Depth of field doesn’t work on its own either. It interacts with shutter speed and ISO, the other two pillars of the exposure triangle. Improving in one area naturally leads to a better understanding of the other two.