Depth of field is the distance between the nearest and farthest objects in a photo that are in focus. A camera can capture a very shallow depth of field by having a wide aperture or a narrow depth of field with a closed down aperture.

Knowing what depth of field is and how to work with it when it comes to photography will allow you to have more control over the look of the final image adding additional impact to your images. This can be an emotional response or simply to focus the viewers eye where you want them to look.

F-Stop

The most common and often used method for adjusting the depth of field is by adjusting the f-stop, or aperture, of the camera. The f-stop setting will either increase or decrease the focal length. If the f-stop is set wide open or at a low number such as f1.4, the depth of field will be shallow. If the f-stop is set narrow or at a higher number such as f22, the depth of field will be deeper. Try this by taking the same picture with the f-stop at f2.8 or whatever your widest option is, and take the same picture at f22. It will be possible to see the difference in depth of field when comparing the two images.



Focal Length of Lens

The distance between the object being photographed and the lens will also affect the depth of field. The further away the subject is from the camera, the further the depth of field will increase. When taking a picture of mountains using a wide-angle lens, almost everything will be in focus. Yet, while using a macro lens to photograph flowers or other small objects, the camera is extremely close which will result in a very narrow depth of field in the picture.

Flower showing Depth of Field
Flower photographed with a macro

Distance of Object

The distance between the object being photographed and the lens will also affect the depth of field. The further away the subject is from the camera, the further the depth of field will increase. Similar to the previous experiment, set your cameras aperture wide open, or to a low f-stop. Then take a picture of an object or person from 2 to 4 feet away. Then to around 10 feet away and take the same picture. When cropping the image to have the same framing you should see more depth of field in the picture taken from further aware compared to the once closer.

depth of field
Distance to object showing narrow depth of field

In Summary

Understanding the effect of the distance between the object being photographed and the lens is key for taking a great photograph. A shallow depth of field is used to focus on one particular element in an image, while a deep depth of field can be used to show many different elements.

The result in narrowing down the focus of the image to what the photographer would like the viewer to see and allows the photographer to control the interpretation of the scene. By selectively using depth of field, photographers can create a professional-looking effect which not only will make the images more enjoyable to view.