Many photographers, especially when starting out, have a difficult time understanding depth of field. I also hear quite often that photographers are waiting for nice weather to get out and shoot. So, here’s a fun exercise you can do at home, in any weather, that will help you understand the finer aspects of depth of field.
Depth of field is determined by which aperture you choose, what focal length you’re using, and the distance between the camera and the subject. In this example, we’ll explore depth of field using a 100mm lens.
To set up
Find between one and three small objects you can photograph. I found three sports water bottles with balls on the top to shoot. Next, you need some studio space. A patio door or very wide window works well.
Your next step is to set up your object, or objects, in front of the window and to place your camera in position. The object and camera should be parallel to the window.
I put the first ball, the soccer ball, about 12 inches in front of the cabinet. Then I put the second ball, the baseball, about 24 inches in front of that. I put the third object, the basketball, 24 inches in front of the next object, and finally I set my camera about two feet in front of the last object.
You’ll need to play a little bit to see what works best for you. It will vary depending on the size of the object you are shooting, and the focal length you are using. You want to be able to focus on all three objects, and take a photo of them without moving your camera, so play for a minute. Focus on the first object and make sure you can see all three objects in the frame. Then focus on the second and make sure you can still see them all. Lastly, do it with the third one, too.
Set your camera on either aperture priority or manual exposure, and use the widest aperture you have. I chose f/2.8. Your lens might not have that aperture available, if so f/4 or f/4.5 will be just fine.
Shoot wide opened focusing on each object in turn
Now, without changing anything but your focus, take a photo of each of the three objects.
This photo was shot at f/2.8 while focused on the object closest to the camera, the basketball. Notice the narrow depth of field, in other words, how blurry the background is.
This was also shot at f/2.8, but this time, I focused on the middle object, the baseball. Notice that it is blurry in front and in back.
This photo was also shot at f/2.8, but I focused on the soccer ball. I did not change camera position nor did I change lenses. Notice the depth of field, but also notice the change in perspective. Can you see that more of the cabinet is in the photograph?
Next shoot with a small aperture
Now, let’s try something a little different. Instead of shooting at your widest f-stop, shoot at your smallest, which means a higher number, like f/32 or f/16.
Here is the same situation. The camera hasn’t moved, but the aperture is now at f/32. The focus is on the basketball, but look how much is sharp.
Look closely. The aperture is still at f/32, but the focus has changed to the baseball. Notice the basketball is more out of focus, but the soccer ball in the back looks pretty sharp.
Above is the third example. The focus is on the soccer ball.
You can practice each of these things with different f/stops to see the difference between f/4, f/8, f/11, f/16 and f/32. Each choice will change the depth of field.
Change the distance to the subject
In the above photograph, I moved the camera closer to the baseball and shot at f/2.8. Practice isolating the elements and see what happens. Notice how the baseball really stands out, and look at the background. By isolating the baseball with a very narrow depth of field, the background becomes really out of focus. This tool is very helpful to clean up backgrounds.
Then I changed my focus to the soccer ball. The aperture is still at f/2.8. What do you notice about the background?
In the shot above the soccer ball is still in the original position, about a foot away from the cabinet. Notice how sharp the background is – this was shot at f/32.
Now, notice how we start to lose detail in the cabinet behind. This image above was shot at f/11.
Finally, by shooting at f/2.8, and without moving the position of the soccer ball or the background, the background has become more out of focus and less distracting.
Take some times and practice this at home. So what you’ve learned here is a great way to practice depth of field at home–even on a rainy day! So take out your camera, find some small objects to shoot and start practicing.
Please share in the comments below how controlling the depth of field could impact how you shoot. What did you learn by doing this exercise?