Understanding Depth of Field for More Creative Control over Your Photos
Many photographers have heard about the concept of Depth of Field (or DOF). Some only have a vague idea of what it means while others have a good grasp for it but still struggle to put it in practice. Understanding depth of field is fundamental for any photographer, travel photographers included, because it provides control over the resulting look of the image. So if you are ready to enhance your travel images and make the most use of the opportunities that come your way, it’s time to master the depth of field in your photography.
Depth of field is the distance that appears acceptably sharp in an image. In other words, it covers the area in your photo where everything is in focus. The quality of DOF can be described in two ways: high (or deep) DOF and low (or shallow) DOF.
High DOF means that the focus range in the image is high, or, simply, that all or most of the image is in focus.
Low DOF means that the focus range in the image is narrow: the focus is on the subject that looks sharp, whereas both foreground and background of the image are blurred.
So how does this knowledge apply in practice? As you set up your image, you most probably already know whether this will be a landscape, a portrait or a close-up detail. This is also the moment when you decide whether all the details in your photo should be in focus, or you will focus on your subject only to separate it from the background. This is where the notion of DOF comes into play.
DOF is determined by 3 factors:
The size of the aperture determined by the f-stop number (or the opening of the lens) is the simplest way to control DOF.
A small f-number (for example f4) corresponds to a large aperture that creates a shallow DOF, whereas a high f-number (for example f18) corresponds to a small aperture that creates a deep DOF. Sounds complicated, right? Here’s the easy way:
Using a high f-number and high DOF is usually best for landscapes, street views, or any other scenes that involve multiple subjects, when you want to make sure that all the details of your image are nicely sharp.
Low f-number and low DOF work best for portraits, close-ups, macro photography, or any other situation when you want to separate your main subject from the background and focus on it, keeping the rest of the image blurred and thus not distracting from your subject.
2. Focal length of the lens
Understanding the effect of the focal length of the lens is also important when speaking of DOF. Simply put, the more you zoom, the lower is DOF. Therefore, the image taken with a wide-angle lens will result in a high DOF, where everything will be more or less in focus, even with a small f-number. So if you want to blur the background more, simply step back and zoom in to achieve this effect.
3. Distance between the lens, subject and background
The distance between the camera, your subject and the background will also have an effect of the DOF effect. To get a nice blurred background, make sure you are close to your subject and that the background behind it is further away to create the actual depth (hence the term depth of field). In the example below, the image on the left shows that there is a fair distance between the first ceramic apple and the last one in the row, making it possible to play with the DOF. In the photo on the right, the two ceramic cats are against the wall. There is hardly any distance (no depth) between them, making it impossible to apply any Depth Of Field.
To sum it all up, here is a chart on how to achieve the highest or the lowest DOF:
The best way to grasp the concept is to practice it yourself. Here’s a simple assignment: find a subject close to you and take three photos of it with three different aperture settings: F 2.8, F11, F18. Then take two more photos of the same subject, one with a lens zoomed out and another with the lens zoomed in. Finally, take a few more images of the same subject from different distances. Look at the differences between all your images and practice until it becomes easy and natural to get the results you are looking for.
Once you have mastered your new Depth Of Field skills through some tests and exercises, it is time to go out and get creative for some real photography. Don't be shy and show us your results.
About the Author
Nadia is passionate about the visual aspect of life and the personalities she meets along the way. Living in the heart of Paris, Nadia never stops exploring the City of Light through her camera and readily shares her knowledge and love for photography.