Using Depth of Field to Enhance Your Photos
Once you’ve learned the basics of creating a photograph and you start to experiment with creating more imaginative images, changing the depth of field starts to enter into the
process. Depending on how much of the image that you want in focus will determine what depth of field to use. (This is purely subjective, since only you know what you are trying to
achieve in the photo.)
What is depth of field?
Simply put, it is the distance between the closest and farthest objects in a photo that appears acceptably sharp. In every photo, there is a certain area of the image both in front of and behind the subject that will appear in focus. A deep (or large) depth of field is used for landscape images, while a shallow (or small) depth of field is used in portraiture, so if you want to include a lot of detail in your photo, use a deep depth of field; if you want to isolate your subject from the background, use a shallow depth of field In the images below, the depth of field starts out deep and gradually goes to shallow, to illustrate the difference in f/stops.
How to control the depth of field
Depending on how you set the f/stop on your camera controls the depth of field. (The f/stop, also known as the aperture also controls how much light is allowed to reach the sensor.) A small number or f/stop means a large opening, while a large number or f/stop means a small opening. This can be somewhat confusing, since usually we think of a small number equating to something small, and a large number equating to something large. WPS Founder and Director E. David Luria suggests you remember it this way:
“At f/2, two people are in focus, at f/22, twenty-two people are in focus.”
Another way to think of it would be: small (number) f/stop, small or shallow depth of field – less in focus; large (number) f/stop, large or deep depth of field – more in focus.
This technique is something that you can practice at home and become familiar with how your camera and various lenses achieve different looks using depth of field. Then, when you are able to go out again, you will be able to put the technique into practice without hesitation.