Depth of field is the area within a photo that appears sharp and in focus. There is a focus point (where you actually focus your lens) in every image. But there is also an area in front of and behind your focus point, which also makes it look sharp, and this area corresponds to the depth of field.
The sharp area varies from photo to photo, depending on various factors such as aperture and distance to the subject (described in more detail below).
So by adjusting your camera settings and composition, you can determine how much of your image will be in focus and how much of your image will be blurred.
You may have heard of the term depth of field (DoF), but what is depth of field and how can it be controlled for artistic results?
In this article, you will learn all about depth of field. Let’s dive in!
What is Depth of Field?
Depth of field is the distance between the closest and farthest objects in a photo that appears acceptably sharp. Now your camera can only focus sharply on one point. But the transition from sharp to fuzzy is gradual, and the term “reasonably sharp” is a loose one. Without being overly technical, how you will see the picture and what size you will be looking at it are factors that will contribute to how acceptably sharp a picture is! it also depends on what! so good is your vision!
Scientifically it is based on what is known as a circle of confusion. That involves more physics than I’m going to address here! Spencer talks about this in his article “Hyperfocal Distance Explained”. Check out that for more technical details if you’d like.
In these two sketches I have tried to illustrate what is meant by a large and narrow DoF. A narrow DoF photo has only a small portion of the image in focus the scene is sharp.
Video Demonstration:
Although this article has plenty of sample real-world photos, we shot a full depth of field tutorial that might be helpful to you if you are the type of person who prefers to learn through video demonstrations. You can see it here:
Photo Demonstration:
Now let’s show some sample photos of how to change the depth of field for a specific scene. First off, I wanted to show you the settings I used to take the sample images in this article. Hopefully this gives you a little more information in the photos and a better sense of the distances between the objects being photographed. To change the distance of the subject from the camera, I moved my tripod closer / further away from the accessories. All test images were taken with the same camera, a Nikon D500.
Aperture:
The aperture is the opening in your lens that lets light through the sensor. Think of it as the pupil for your lens. It expands to let in more light and contracts to restrict light when it is bright. Opening it is probably the first thing to do. Most photographers consider when to adjust the depth of field.
Large apertures, which are correlated with small f-numbers, produce a very shallow depth of field. Small apertures or large f-numbers, on the other hand, produce images with a large depth of field.
Captured with a NIKON D800 and 24-70mm f/2.8 lens @ 24mm, ISO 200, 8/10s, f/22.0
This image has a large DoF. I focused on the rocks about 5 meters in front of me. The rocks in the foreground and distant clouds are all in focus.
Captured with a NIKON D500 and 17-55mm f/2.8 lens @ 22mm, ISO 200, 1/1600s, f/2.8
This image has a low DoF. Here I focused on boxing gloves.
Camera-Subject Distance:
Another important factor that affects the depth of field is the distance between the camera and the subject, the shorter the distance, the smaller the depth of field.
Have you ever tried to take a close-up picture of a flower or an insect, but can’t get the entire subject in focus even with a small aperture? Because the closer you are to the subject, the shallower the depth of field.
Look at these two sets of images. The distance between the subject and the camera in the first group of images is 1.5 m. After each shot, I stopped the opening. The second set has a focus distance of almost half a meter. Notice two things. In each image set, the DoF increases as the aperture narrows.
For photos taken with the same aperture, the depth of field is greater the greater the distance from the camera to the subject.
Just a quick note. There are a variety of depth of field calculators that are available online. You can also download DoF applications to your phone. All DoF values mentioned in this article were calculated using the Simple DoF Calculator app for my iPhone. You can find the actual formulas for calculating the depth of field here.
Focal Length of the Lens:
Wide-angle lenses (short focal lengths) have a greater depth of field than telephoto lenses (long focal lengths) – well, not exactly! It’s not that easy. If you take a picture and the subject on the remote camera does not change, it will. You can see this in these two pictures below.The top set was taken with a focal length of 70 mm.
The floor is set to 105 mm. Both sets were recorded at a distance of 2 m from the test subject. Note that for any pair of images captured with the same aperture, the DoF will be higher for the narrower focal length lens.
Determining Depth of Field:
Many DSLRs have a depth of field preview button. If you press this button while looking through the viewfinder, the camera will stop the lens and you will see what the actual picture will look like. However, if the aperture is small, the viewfinder will. . It will be very dark and it will be difficult to see the preview.
Live View can also be used on some camera models to preview the DoF. Check your owner’s manual to see if your DSLR can do this.
Mirrorless photographers may have an advantage over DSLR photographers because the photo will usually look what the photo normally looks through the digital viewfinder or on the LCD screen.
Conclusion:
In my opinion, it’s not worth worrying about how many inches the DoF is in an image; it would completely take the joy of photography away from you. Knowing when to need a small DoF and how to create it is much more important. The same is true if you need a large DoF. The beauty of digital is that you can take a photo and then view it on the LCD screen. Checking the image quickly is a lot easier than taking out the phone and calculating the DoF!
If you don’t get the result you want, try changing the distance of the camera object or the lens iris to get the effect you want.
Knowing what factors can affect a photo’s depth of field gives you the artistic freedom to create the images you want. You will learn more by doing. Take the time to experiment with your camera; get to know it better. Try different focal length lenses, change the aperture, move your feet to change your perspective. Analyze your photographs so you know how your gear performs. Then when it comes time to take pictures that really count, you will be ready.
