Aperture and Depth of Field

Aperture (measured in f/stop) controls the size of the lens opening that allows light into your camera. You can blur the foreground and background that bracket your subject (known as shallow depth of field) by opening up the aperture with a low f-stop number; alternatively, you can keep your photo sharp from the foreground through to the background (known as wide depth of field) by closing the aperture down with a high f-stop number. Depth of field is defined as being the distance between the nearest and the furthest objects giving a focused image – a small depth of field comes with a lower aperture value, and leads to very little being in focus whereas a larger depth of field comes with higher aperture values and makes more of an image be in focus.

Focal Length

Focal length (usually measured in mm) is defined as being the optical distance from the centre of a lens and its focus. This determines what you see when using the camera, for example a shorter focal length captures more due to a wider angle.

Auto vs Manual Focus

Auto focus is typically general use due to its simplicity, whereas manual focus is used more when close ups and fine detail are needed in an image. When using manual focus, you should use the focus ring on the end of the lens and adjust for each shot as necessary.

Example photos using aperture:

Aperture of 2.8:

In this photograph, the toy plane is noticeably much more in focus compared to other objects in the background, highlighting it as the main subject of the image. This low aperture creates a very shallow depth of field, creating this low focus effect on the background.

Aperture of 5.6:

When compared to the previous image, this one is very similar in terms of the plane still clearly standing out as the subject/main focus – however, a slightly higher aperture value has enlarged the depth of field which consequently has made the other objects captured in frame more in focus.

Aperture of 11:

As the aperture value continues to increase, the depth of field clearly becomes larger which as a result makes even more of the objects captured be in focus. Due to the depth of field not highlighting one particular aspect of this image, there is no singular main focus which implies everything captured in this image is of equal importance.

Aperture of 22:

Finally, with a very high aperture value, the depth of field is very large leading to every object being completely in focus which further emphasises the effect of equal importance first noticed at an aperture value of 22. Blurs are also minimised, which can be useful for capturing images where you want everything to be in focus (such as landscapes, nature etc.)

Artist Research: Uta Barth

Over the last twenty years, Uta Barth has focused her art on how we perceive visuals. Known for her “empty” images that focus on painterly abstraction, she skillfully creates blurred backgrounds, cropped compositions, and plays with natural light to seize those quick, almost unnoticed moments that usually linger at the edges of our vision. By intentionally stepping away from traditional photography and the typical use of a camera, Barth’s work thoughtfully breaks down the norms of visual representation, highlighting the boundaries of what we can actually see.

Some of my work, inspired by Barth:

To achieve the soft focus effect Barth uses, I used a low aperture value as well as manual focus. However, I feel like this wasn’t very successful at capturing the abstract nature of Barth’s work since my image’s focus was slightly too sharp to achieve this – furthermore, I believe the scene I have captured was a poor choice for trying to achieve an abstract effect due to a large variety of things present in the image (chairs, blank walls, door with a light that clearly stands out). To improve next time, I will adjust the f/stop value to be even lower to really try and strive for a shallow depth of field and I will photograph a less vibrant scene with less objects and things to look at to maximise the chances of me capturing the abstract effect used by Barth.

Above is the same image but edited using Photoshop – I found the original image to be too vibrant and colourful to qualify as abstract, so I toned down the saturation to better achieve an abstract effect. Furthermore, I cropped out most of the image to reduce the amount of things present to try work towards more of an abstract effect; overall, I think I could definitely do better if I had adjusted my aperture values properly to achieve a low focus effect.

My work compared to Barth’s:

My work against a picture taken by Uta Barth. My work is clearly not very abstract since the objects captured can be clearly identified and the colours are vibrant which makes the scene even less abstract; in comparison, Barth’s image uses softer colours which blend together naturally as well as a much shallower depth of field, successfully creating an abstract effect.