Aperture (Depth of field)

The depth of field is an important aspect of photography that refers to the range of distance in a photograph that appears acceptably sharp to the viewer. When a photograph has a shallow depth of field, only a small portion of the image will be in focus, while the rest will be blurry. On the other hand, a photograph with a large depth of field will have a greater range of distance that appears sharp, allowing the viewer to see more detail in the image.

The depth of field can be adjusted by choosing different aperture values on the camera. Aperture refers to the size of the opening in the lens through which light passes. A larger aperture (smaller f-number) will result in a shallow depth of field, while a smaller aperture (larger f-number) will result in a larger depth of field.

Understanding and controlling the depth of field is important because it can greatly affect the overall look and feel of a photograph. For example, a portrait with a shallow depth of field will draw attention to the subject by blurring the background, while a landscape with a large depth of field will allow the viewer to see all the details in the scene.

In order to illustrate the effect of different aperture values on the depth of field, we have included a couple of pictures. These images demonstrate how the depth of field can be changed by simply adjusting the aperture, giving you an idea of the creative possibilities available to you when controlling this aspect of your photography.

Test equipment

Canon EOS 40D

Canon EF 50mm f/1,8 II

Test setup

The camera is standing on a tripod next to a kitchen table (to make sure we do not change the distance from the camera to the objectives) and on the table we have a few glass cans of spices. Nothing fancy and advanced - so you can easily do this yourself.

Test results

These images will show the result of a different aperture value while having the rest of the test equipment and setup untouched.






The different combinations will all give you a nice and faultless picture, but by changing the aperture you can get the desired depth of field in your picture. Using a very low aperture such as f/1,8 may be good if you in a portrait only wish to set the eyes in focus but the rest slightly out of focus. This becomes possible because the f/1,8 aperture gives a very short depth of field. If you are looking for the possibility to take pictures with a very short depths of field you should look for a bright lens, where the maximum aperture value is low.